About this List
Telephony and Computer Terms

These definitions have been gathered from many sources and are for the most part correct. The collection was made to help clear up the confusion with so many terms and to consolidate this information thus giving a common bases for discussion about things in the telephone and computer industry. Since the industry is in a constant state of flux these definitions will also be in flux. Today’s definition is tomorrow's history. The major problem in developing any such extensive list of terms is determining what to put in and what should be left out. This list should contain a sufficient number of terms to help explain most commonly used abbreviation. If any are seriously lacking please email me BillSquires@theolddub.com and let me know so that I can add them into this list.

10Base2: A physical layer communications specification for 10Mbps, baseboard data transmission over a coaxial cable (Thinnet) with a maximum cable segment length of 200 meters.

10Base5: A physical layer communications specification for 10Mbps, baseband data transmission over a coaxial cable (Thicknet) with a maximum cable segment length of 500 meters.

10BaseF: A physical layer communications specification for 10Mbps, baseband data transmission over a fiber-optic cable.

10BaseT: A physical layer communications specification for 10Mbps, baseband data transmission over a twisted-pair copper wire.

400si: Samsung’s DCS II, a phone switch.

802.x: The set of IEEE standards for the definition of LAN protocols.

AA: Automated Attendant, is a device/logic machine that answers and processes/cascades/streams/screens incoming calls. It can direct callers to certain preprogrammed options such as extension directories or allow access to live operators/attendants.

A & B (Robbed) Bit Signaling: Procedure used in most T-1 transmission links where one bit, robbed from each of the 24 sub-channels in every sixth frame, is used for carrying dialing and controlling information. A type of in-band signaling used in T-1 transmission. A & B signaling reduces the available user bandwidth from 1.544Mbps to 1.536 Mbps.

A-bit: One of the signaling bits used in Channel Associated Signaling. On standard T1 two signaling bits are used (A and B). In other signaling protocols four signaling bits may be used (A, B, C, and D).

ACD: Automatic Call Distribution/distributor. A system which passes callers to an open line. These inbound calls may be parked or in a queue, and are processed and distributed via a specific call routing logic. ACD often adjoins Private Branch Exchange switches (PBXs).

ACK: Acknowledgment, A type of message sent to indicate that a block of data arrived at its destination without error.

A-Law: The PCM coding and companding standard used in Europe. The method compress 14 bits of audio to 8 bits of compressed PCM. The method of encoding sampled audio waveforms used in the 2.048Mbit 30 channel PCM primary system, widely used outside North America. See also: µLAW.

ADSL: Asymmetric Digital Subscriber Line. A revolutionary method of compressing and multiplexing data on a POTS line PSTN network. ADSL is currently offered by Bell Canada as a 64kbps upstream and 1.54Mbps downstream facility over standard long copper links. Bandwidth as high as 52Mbps has been promised. The future of ADSL is in part that it presents a more direct migration path to ATM, than does ISDN. ADSL, on the surface, providing transparent data pipes at various rates over POTS. To create multiple channels, ADSL modems divide the available bandwidth of a telephone in one of two ways: Frequency division multiplexing (FDM) or echo cancellation. FDM assigns one band for upstream data and another for downstream data. The downstream data-path is then divided by time division multiplexing into one or more high-speed channels and one or more low-speed channels. The upstream path is also multiplexed into corresponding low speed channels. Echo cancellation assigns the upstream band to overlap the downstream, and separates the two by means of local echo cancellation, a technique well known in V.32 and V.34 Modems. Echo cancellation uses bandwidth more efficiently, but at the expense of complexity and cost. With either technique, ADSL splits off a 4KHz region for POTS at the DC end of the band. An ADSL modem organizes the aggregate data stream created by multiplexing downstream channels, duplex channels, and maintenance channels together into blocks, and attaches error code to each block. The receiver then corrects errors that occur during transmission up to the limits implied by the code and the block length. The unit may also be set to create super-blocks by interleaving data within sub-blocks; this allows the receiver to correct any combination of errors within a specific span of bits. Initial trial indicate that the correction used in ADSL will create effective error rates suitable for MPEG2 and other digital video compression technologies.

ADPCM: Adaptive Differential Pulse Code Modulation codecs are waveform codecs which instead of quantizing the speech signal directly, like PCM codecs, quantize the difference between the speech signal and a prediction that has been made of the speech signal. If the prediction is accurate then the difference between the real and predicted speech samples will have a lower variance than the real speech samples, and will be accurately quantized with fewer bits than would be needed to quantize the original speech samples. At the decoder the quantized difference signal is added to the predicted signal to give the reconstructed speech signal. The performance of the codec is aided by using adaptive prediction and quantization, so that the predictor and difference quantizer adapt to the changing characteristics of the speech being coded.

Advisory tones: The dial-tone, busy signal, dialing signal heard when using a phone system. Produced by telephone company to provide caller feedback.

Aliasing: Distortion in a signal. In video when sampling rate interferes with the frequency of program material. Spectral aliasing is caused by interference between the luminance and chrominance signals.

AMI: Alternate Mark Inversion , A method on T1 digital lines of representing '1' bits by voltages of alternating polarity.

AMIS: Audio Messaging Interchange Specification, A protocol governing the exchange of voice messages and other information between Voice Mail and Voice Processing systems. This standard allows some degree of inter-operability between equipment from different vendors who support the protocol. Two separate AMIS protocols are defined - digital and analog.

ANSI: American National Standards Institute, This organization is responsible for approving U.S. standards in many areas, including computers and communications. Standards approved by this organization are often called ANSI standards

ANI: Automatic Number Identification is a Telco service (similar to CallerID or CLID) which allows a recipient to determine the number and other call information of the caller BEFORE the call goes through. ANI is supported on Centrex and ISDN ONLY, and NOT T1 or DEA. CallerID on the other hand places the signaling information WITH the call, so the phone set rings at the same time that the information about the call is made available. In Canada, front bone for telephony is provided ONLY from Bell Canada (and its subsidiaries), hence, signaling services which other carriers, especially long distance carriers support, but do not provide to the demarcation point. ANI is touted as a compelling service of ISDN, although really an attribute of Signaling System 7 (and therefore distinct from ISDN) and one can get ANI from other Telco services such as Centrex. ANI is becoming synonymous with Caller ID.

Answer Mode: When placing outbound calls and transfers, the VRU system must determine whether the call/transfer has been successfully answered. This is done using call progress detection to analyze the incoming voice signal for call progress tones (ringback, busy tone, fast busy, etc) and voice. Which conditions indicate a successful answer may differ depending on the situation. For example, one might want to handle an outbound FAX call differently than a call to a person.

Answer supervision: A signal returned to the caller from the CO to indicate that the called party has taken the phone off-hook (picked up) and that the line has been 'nailed-up' to initiate billing or usage algorithms.

API Application Programmer Interface, is a software library that allows a programmer to interface with a system or device. These are usually supplied by the manufacture of the device or software program.

ASCII: American Standard Code for Information Interchange. ASCII is a 7-bit coding scheme used by small computers for converting letters, numbers, punctuation and control codes into digital form. IBM mainframes use another form of basic information interchange (enhanced ASCII).

ASP A company that provides application hosting services is commonly called an Application Service Provider (ASP). An ASP installs, configures, and maintains enterprise-class software on its own servers and allows its customers to access the software remotely, normally over a secure Internet connection. In addition to the software application and server hardware, the ASP provides data storage space, data backup services, network technicians, and continuous, server-based upgrades. The customer typically accesses the hosted application using an Internet browser.

Asynchronous Asynchronous Transmission, A method of data transmission which allows characters to be sent at irregular intervals by preceding each character with a start bit, and following it with a stop bit. It is the method most small computers (especially PCs) use to communicate with each other and with mainframes .

ATM: Asynchronous Transfer Mode is a cell-switching and multiplexing technology designed to combine the benefits of circuit switching (constant transmission delay, guaranteed capacity) with those of packet switching (flexibility, efficiency for intermittent traffic). Like X.25 and Frame Relay, ATM defines the interface between the user equipment and the network. ATM differs from synchronous transfer mode methods, where time-division multiplexing techniques are employed to pre-assign users to time slots. ATM time slots are made available on demand, with labels identifying the source of the transmission contained in each ATM cell.

Attenuation: The decrease in power of a signal, light beam, or light wave, either absolutely or as a fraction of a reference value. Usually occurs as a result of absorption, reflection, diffusion, scattering, deflection or dispersion from an original level and not normally from geometric spreading (i.e., the inverse square of distance effect). Attenuation is measured in decibels (dB), and is the opposite of gain.

B Channel: Or bearer channel, is a fundamental component of ISDN interfaces. It carries 64,000 bits per second in both directions (duplexed), is circuit switched and is able to carry either voice or data. Whether it does or does not depends on how your Telco has tariffed its ISDN service.

Bandwidth: The number of bits of information which can move over a communications medium in a given length of time.

Basic Rate Interface: An ISDN service package which includes 2 B or Bearer channels (full duplex @ 64 KBPS) and one D or Data channel at 16Kbps. Commonly referred to as 2B+D. Ideal for SOHO CT applications because of tip & ring connectivity.

Baud: The measure of transmission speed over an analog phone line. The number of changes per second in the analog sine wave carrier signal (3kHz). Often confused with bits per second. See Modem.

Back Bone: The main connection infrastructure of any networking system, see also Local Loop

big-endian: A format for storage or transmission of binary data in which the most significant bit (or byte) comes first. The term comes from "Gulliver's Travels" by Jonathan Swift. The Lilliputians, being very small, had correspondingly small political problems. The Big-Endian and Little-Endian parties debated over whether soft-boiled eggs should be opened at the big end or the little end.

BIOS: is an acronym for Basic Input Output System. This is the built-in software that determines what a computer can do without accessing programs from a disk.

Blind Transfer: A transfer where one completes the transfer before waiting for the transfer party to answer the call. It is possible for the caller to be transferred to a call that is RingNoAnswer.

BPV: BiPolar Violation, On T1 trunks which use Alternate Mark Inversion (AMI) when two successive '1's of the same voltage polarity are received.

BRI: Basic Rate Interface, ISDN trunk which provides 2 B channels of 64kpbs voice, and 1 D channel for signaling information. This type of ISDN trunk is typically used to a single user at their home or office. Typically a Primary Rate Interface (PRI) trunk is used to connect to an IVRU system.

Bridge: A device which forwards traffic between network segments based on datalink layer information. These segments would have a common network layer address.

Broadband: A transmission medium capable of supporting a wide range of frequencies. It can carry multiple signals by dividing the total capacity of the medium into multiple, independent bandwidth channels, where each channel operates only on a specific range of frequencies.

Busy Out: To hold a phone line offhook to prevent its use while the system is not ready to receive an inbound call.

CADENCE: Voice Mail software running on the Single Board Computer (SBC) and all the third party drivers and utilities residing on the SBC

Call Progress: Telephony signaling providing by a PBX/ACD/switch to indicate the progress of the call. Includes ringback, busy, fast busy, SIT tone, and error tone (turkey tone).

CallerID, CLID or CID: Is a Telco provided service, or Centrex service. CallerID supports the signaling of information to a telephone set that is CallerID-capable (has an LED screen) and this call information is delivered WITH the call. Not to be confused with ANI.

Call control: Signals used to start/setup/nail-up a telephone call as well as monitoring the call and terminating/tearing it down.

Call center: A physical or virtual/distributed location for centrally managed calling (inbound or outbound or both). Staffed by agents, the call center typically consists of an ACD/PBX with a CTI link (such as a Nortel Meridian One with Meridian Link or Comdial DXP Plus with Enterprise CT-Connect), a call control system/server such as Dialogic CT-Connect, a database/database management system such as Sybase 11, a LAN and a high level, software-based, multi-functional call/record management system like Versatility Series.

CAS: As in CAS compliant. A Communicating Applications Specification is a high-level programming interface developed by DCA and Intel. This standard permits fax boards to offload data processing (such as rasterizing an image) from a CPU thus drastically accelerating the process of transmitting a fax.

CCIRN: Coordinating Committee for Intercontinental Research Networks, A committee that includes the United States FNC and its counterparts in North America and Europe. Co-chaired by the executive directors of the FNC and the European Association of Research Networks (RARE), the CCIRN provides a forum for cooperative planning among the principal North American and European research networking bodies.

CCITT: Comite Consultatif International de Telegraphique et Telephonique

Centrex: A Telco leased service from the local CO, which typically includes intercom, call forwarding, call transfer, toll restrict, least cost routing and call hold on single lines. Centrex is a software package which might also include Extended Service Packages like CompuCALL on the Nortel DMS-100.

CGI: Common Gateway Interface. It defines a method for a Web server and an outside program, such as a database, to share information through on-line forms and gateways.

Channel: A transmission path between two points. It is usually the smallest subdivision of a transmission system by means of which a single type of communications service is provided.

Channel Process: also known as Channel The thread of execution with in the Voice Subsystem which controls execution of commands for a call. The distinction between channel and line must be understood. The VFUTIL utility shows the state of all Channel Processes within the Voice Subsystem. The System Monitor utility shows the state of all lines within the Voice Subsystem.

CISC: Complex instruction set computers use long instructions with longer clock cycles and lower scaling to process data.

CIT: Computer Integration Telephony is a term used by Digital Equipment Corp.

CLASS: Custom local access signaling service is a subset of SS7 and includes services such as ANI, distinctive ringing, call waiting, selective call forwarding, selective call screening.

Cleardown: Many phone switches provide some tone to indicate that the remote party has dropped. In many situations the system can be configured to detect this Cleardown tone and end the call. Cleardown tones are not standardized and will differ between PBX/ACD vendors and between countries

Clustering: 1. A method of super-computing that involves connecting groups of computers to share in compute tasks and processes. Synonymous to networked, pre-emptive multi-tasking. Most commonly used in digital animation studios instead of massively parallel supercomputers.

2. A method of sharing resources for fail-over. Commonly applied to separate servers that share a drive tower or RAID. The most prevalent, affordable, secure and powerful server clustering technology and platform today is still DEC VMS/OpenVMS, UNIX being still a very distant second.

CO: Central Office of a Telco. Usually a nexus or main node consisting of switching and head-end equipment. Connects subscribers' lines to other lines local and long distance. Sometimes referred to in Europe as Public Exchange.

CODEC: Any one of several speech compression techniques. In the mid 1980s the CCITT standardized a 32 kbits/s ADPCM, known as G721, which gave reconstructed speech almost as good as the 64 kbits/s PCM codecs. Later in recommendations G726 and G727 codecs operating at 40,32,24 and 16 kbits/s were standardized. Code for various ADPCM codecs, as well as the G711 A-law and MU-law PCM, was released into the public domain by Sun Microsystems, Inc.

Companding: A method of representing samples of digitized voice. Two standards of companding are in common use. The MU-LAW standard is used in North America and Japan. The A-LAW standard is used in Europe

Conference: The connecting of two or more parties on a single connection. This typically requires specialized circuitry called a Conference Bridge. Many PBX/ACD systems support conferencing.

Crosstalk: Undesired energy transferred from one voice circuit to another.

CRC: Cyclic Redundancy Check, A number derived from a set of data that will be transmitted. By recalculating the CRC at the remote end and comparing it to the value originally transmitted, the receiving node can detect some types of transmission errors.

CSU: Channel service units are used to connect a digital phone line (T-1 or Switched 56 line) coming in from the Telco to either a multiplexer, channel bank directly to another device producing a digital signal, i.e., a digital PBX, a PC or other data communications device. CSUs perform line conditioning equalization functions and respond to loop back commands.

CT: Computer Telephony is a term which describes the industry that concerns itself with applying computer electronic data processing and transaction services to telecommunications devices and systems, especially switches and phones. It is a primary component of Salesforce Automation (SFA).

CTI: Computer Telephony Integration, This industry buzzword may mean different things to different vendors. Typically it means the exchange of information between telephony system and a host computer for smart handling of phone call routing. For example, a "Screen Popping" application will provide a live ACD agent with the host screen for a caller who is being transferred from an IVR system without requiring the caller to repeat their account ID.

CTS Clear To Send is a status line associated with a transmission control such as RS232.

Cut-Thru: The ability for a voice prompt to be interrupted by caller input via DTMF, spoken voice, or pulse/rotary.

D4 Framing: The standard protocol for providing framing across a T1 link used for standard switched telephony operation. The framing consists of a standard repeating bit pattern on the digital link which allows each side of the T1 circuit to synchronize with each other.

Datagram: A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination.

dBmV and dBµV: This is a CATV measurement of signal strength referenced to voltage are measured in dBmV or dBµV. The signal value of dBmV is in reference to a 1mVrms output and represents a ratio of voltage. The equation { 20 log(Vout in millivolts/1mV)=dBmV } describes this signal strength. Note that 8 dBmV represents a signal of only 8.4E-05 milliwatts on a 75 ohm line.

DEA: DEA is the standard DS1 Access into the (Nortel DMS-100) Public Switched Telephone Network for Multi-Purpose Usage. This service is based on the North American Standard DS1 (1.544 Mbps) transmission rate with signaling being carried on a per channel basis (using A+B robbed-bit signaling) similar to T1 at 64Kbps but different from MegaLink PRI which uses one D channel to carry the signaling for all 23 Bearer or Voice/Data Channels. Basically, DEA is the Non-ISDN Digital Access to the DMS-100 at 1.544 Mbps where each channel is capable of 56Kbps-digital throughput. DEA used to be called MegaRoute.

DCE: Data Circuit-Terminating Equipment.

DCS: Digital Communications Switch, this phone switch is made by Samsung.

DCSII: Larger version of the DCS

D Channel: An ISDN interface that is used to carry control signals and customer call data in a packet switched mode. This is what gives ISDN its advanced signaling capabilities (such as ANI) over T1, which uses less efficient and powerful A+B Robbed-Bit signaling.

DHCP: The Dynamic Host Configuration Protocol (DHCP) is an Internet protocol for automating the configuration of computers that use TCP/IP. DHCP can be used to automatically assign IP addresses, to deliver TCP/IP stack configuration parameters such as the subnet mask and default router, and to provide other configuration information such as the addresses for printer, time and news servers.

Dial Tone: A signal provided by telephony equipment to indicate that they are ready to receive dialed digits. Most PBX/ACD(s) provide dial tone after a line goes offhook, or after a flash.

Distributed computing: The process by which data and applications are distributed to multi-user computers, workstations and PCs within a network rather than maintained on a central computer. A superset of client/server computing.

DID: Direct inward dialing is a capability that allows one to dial inside a company directly without going through the attendant. Used to be an exclusive feature of Centrex, but is now provided by almost all PBXs. One must connect via specially configured DID lines from the CO.

DNIS: Dialed Number Identification Service is a feature of 800 and 900 lines that provides the number the caller dialed to access the attached CT. The DNIS identifies to the CT system the application (ie. FoD) the caller dialed on E&M WinkStart lines this information is provided via inband DTMF digits

DNS : Domain Name System, The DNS is a general purpose distributed, replicated, data query service. The principal use is the lookup of host IP addresses based on host names. The style of host names now used in the Internet is called "domain name", because they are the style of names used to look up anything in the DNS. Some important domains are: .COM (commercial), .EDU (educational), .NET (network operations), .GOV (U.S. government), and .MIL (U.S. military). Most countries also have a domain. The country domain names are based on ISO 3166. For example, .US (United States), .UK (United Kingdom), .AU (Australia). See also: Fully Qualified Domain Name, Mail Exchange Record.

Domain: A level in the Internet administration system which assigns a name to the numerical address of a host computer. For example, the Internet Protocol address is equivalent to the domain name ctsnet.com (the .com suffix indicates a commercial organization; other suffixes include .ca for Canada, .org, .edu, and so on).

DOS Disk Operating System, refers to the lower level of an operating system that interfaces with any HDD storage devices. DOS is most commonly used to refer to Microsoft’s command driven pre-Windows operating systems or other vendors operating systems that use the same command structure. The last released version of DOS only by Microsoft was version 6.22. Windows95 for example runs over a DOS base of 7.0 for compatibility.

Duplex: Two-way, real-time communication capability. As in a telephone but not a two way radio (called simplex).

DS-0: Digital service level 0. The global standard for digitizing one voice conversation at 64 K bits per second.

DS-1/T-1: Digital service level 1. There are 24 DS-0 channels in a DS-1, also known as a T-1 channel in North America (Bell DEA/MegaRoute) at 1.544 M bits per second.


DSP: Digital signal processors are specialized microprocessors that perform the same task (run the same digital manipulation logic/algorithm on an analog signal) repetitively at very high frequency. Most often used in telecommunications and multimedia application platforms.

DSVD: Digital Simultaneous Voice and Data. A new Modem card transmission technology.

DTE: Data Terminal Equipment

DTMF: Dual tone, multi frequency enables electrical pulses representing numbers to the PSTN to be transmitted separately. Same as touch-tone.

E-1 or E1: The basic building block for European multi-megabit data rates, with a bandwidth of 2.048Mbps. The European equivalent of the T-1 standard. E-1 has a higher throughput capacity than T-1. There are Digital Service Units (DSUs) available from companies such as Gandalf (now a division of Mitel) and Shiva that can easily bridge the two circuits.

E3: A European standard for transmitting data at 57.344Mbps. US equivalent is the T3.

ECM: Error Correction Mode, An option within the CCITT FAX protocol which allows retransmission of blocks of FAX data if transmission errors are detected. Both the sending and receiving FAX machines must agree to support ECM during initial T.30 handshaking of this feature will not be used.

EIDE: Extended Integrated Drive Electronics. See IDE.

Email: Electronic Mail, An application that allows a user to send or receive text messages to or from any other user with an Internet address, commonly termed an Email address.

EEPROM: Pronounced double-ee-prom or e-e-prom, short for electrically erasable programmable read-only memory. EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge. Like other types of PROM, EEPROM retains its contents even when the power is turned off. Also like other types of ROM, EEPROM is not as fast as RAM. EEPROM is similar to flash memory (sometimes called flash EEPROM). The principal difference is that EEPROM requires data to be written or erased one byte at a time whereas flash memory allows data to be written or erased in blocks. This makes flash memory faster.

Erlang: A measurement of telephone traffic where one Erlang is equal to one full hour of usage (i.e. conversation). Numerically, traffic on a trunk hen measured in Erlangs, is equal to the average number of trunks in use during any given period in hours.

Erlang B: A probability distribution developed by A. K. Erlang (c. 1912) that describes the estimate of the number of trunks required to carry a given amount of traffic where Erlang B assumes that a random inbound call vanishes and does not return if all trunks are busy. Uses fewer trunks than Erlang C or Poisson formulae, and is easier to program than either. Erlang B is used when there is random traffic and no available queuing.

Erlang C: A formula for designing telephone traffic management for call control systems. Used when traffic is random and there is queuing. It assumes that all callers can wait indefinitely to get through to a service (automated or manual). Therefore, offered traffic cannot be bigger than the number of trunks (minimum limiting factor) available (if it is queue wait will become infinite).

Extranet: A virtual network that uses passcodes and authentication on secure Web, e-mail and HTTP servers that are networked via the Internet to provide users with a restricted data, voice, multimedia communication service. Very often used in lieu of an intranet, and where 'known, outside' users can interact with the host organization.

ESF: Extended Super Frame, A T1 framing method used to uniquely identify the positions of the 24 timeslots for the 24 voice channels. ESF is a more sophisticated method than "standard framing", and provides additional signaling features.

Ethernet: A 10-Mb/s standard for LANs, initially developed by Xerox, and later refined by Digital, Intel and Xerox (DIX). All hosts are connected to a coaxial cable where they contend for network access using a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) paradigm.

FDDI: Fiber Distributed Data Interface. An ANSI standard for a 100Mbps token-passing ring based on fiber optic transmission media.

Far End Disconnect: This term refers to methods for detecting that a remote party has hung up. This is also known as hang-up Supervision. There are several methods that may be used by a PBX/ACD to signal that the remote party has hung up, including cleardown tone, or a wink.

Faxback or Fax-On-Demand: This is when the system receives an inbound call, and then later sends an outbound FAX on the same call. Often this FAX will be in response to user input.

FCC: Federal Communications Commission, The US Government agency that regulates issuers relating to telephony and use of the electromagnetic spectrum.

Finger: A protocol, defined in RFC 1288, that allows information about a system or user on a system to be retrieved. Finger also refers to the commonly used program which retrieves this information. Information about all logged in users, as well is information about specific users may be retrieved from local or remote systems. Some sites consider finger to be a security risk and have either disabled it, or replaced it with a simple message.

Firewall: A gateway (software) between two networks that buffers and screens all information that passes between such networks.

Firewire: see IEEE 1394

First Party Call Control: This always refers to computer telephony that exists in the standalone PC or Client PC in a network. It includes dialing (maybe automated but never full automation such as predictive) from the PC interface and sometimes screen pops from a local database for inbound calling. The telephone set is typically an analogue set that connects to the PC directly via a telephony interface device in the PC. First party call control is used in very small capacity environments, and rarely includes any call management features.

Flash: A signal provided to a PBX/ACD to access special features such as transfers. On LoopStart lines a flash is performed by momentarily dropping loop current.

Flash Memory: A special type of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time. Many modern PCs have their BIOS stored on a flash memory chip so that it can easily be updated if necessary. Such a BIOS is sometimes called a flash BIOS. Flash memory is also popular in modems because it enables the modem manufacturer to support new protocols as they become standardized.

Flash Transfer: A protocol for transferring a call to another party. In this case a flash is used to request an operation from the PBX/ACD. In some cases an additional transfer feature code must be dialed.

Four Wire: A connection that requires 4 conducting paths (wires) for two way communication. Two wires are used for send and two for receive.

FOOBAR See FUBAR. Also a transport password used in the 1970's computer game Adventure.

FLOPS: A measure of processor performance based on floating point operations per second.

Frame: Generally a group of data bits in a specific format, with a flag at the beginning and end of the frame. A logical transmission unit which contains its own flow control information for addressing and error checking. Also, refers to a complete cycle of events in time division multiplexing. The frame usually includes a sequence of time slots for the various sub channels, as well as extra bits for control and calibration.

Frame Relay: Is a managed wide area network infrastructure transmission protocol similar to the PSTN, but not the same as the Internet, which, though still a WAN, is an unmanaged network. Point to point tunneling protocol (PPTP) is now available for the Internet, and though it does not provide a very high or remotely comparable level of management, it does allow for better security, allocated bandwidth and the creation of a crude PVN inside the Internet. Frame relay is a relatively secure network infrastructure because it is managed and traffic is often monitored by the frame relay carrier. Private virtual networks (PVNs) are often created using frame relay.

Framing: A repeating bit pattern used on digital T1 and E1 trunks to allow the two sides to synchronize with each other.

FTP: File Transfer Protocol. A protocol that allows file transmission over the Internet between two computers.

FUBAR: F*cked Up Beyond All Repair. A term adopted from the US military and commonly used in the computer industry to mean that a program or piece of hardware can not be fixed. Commonly misspelled as "foobar" by those that do not know the actual meaning. Usage: "Don’t bother, that system is fubar."

Full Duplex: A communication path which is able to carry information in both directions simultaneously.

G711: See PCM & CODEC

Gain: The increase in signaling power that occurs as the signal is boosted by an electronic device. Measured in decibels (dB).

Gateway: The term "router" is now used in place of the original definition of "gateway". Currently, a gateway is a communications device/program which passes data between networks having similar functions but dissimilar implementations. This should not be confused with a protocol converter. By this definition, a router is a layer 3 (network layer) gateway, and a mail gateway is a layer 7 (application layer) gateway.

Gopher: An Internet tool allowing the user to browse for documents through menus on a computer running gopher server software.

Ground Start/Loop Start: A way of signaling on subscriber trunks in which the tip (plus side of circuit) and ring (minus) are bridged (grounded) to get dial tone.

Group 3: One of the four sets of international standards existing for FAX transmission. Group 3 is the standard used by nearly all standard FAX machines around the world. Group 1 and 2 FAX machines are obsolete. Group 4 FAX machines are expensive, and not yet widely available. Most newer systems supports Group 3 FAX operation.

H.323: An ITU/ECTF standard for transmitting audio conferencing and video conferencing data.

Hacker: A person who delights in having an intimate understanding of the internal workings of a system, computers and computer networks in particular. The term is often misused in a pejorative context, where "cracker" would be the correct term.

Half Duplex: A communication circuit which can carry information in both directions, but only one direction at a time.

hang-up Supervision: Signaling provided by the phone switch to the telephony system to indicate that the remote party in a phone call has hung up. Such hang-up supervision allows the telephony system to immediately free the phone line for another call. Different mechanisms exists to signal hang-up supervision, depending on the line protocol used. On analog, LoopStart lines often a "wink" or momentary loss of loop current is sent to signal hang-up supervision. Other systems may provide special tones known as Cleardown Tones to signal remote hang-up.

HDLC High-level Data Link Control is a LAPB and NRM Level 2 protocol, ISO's (HDLC) uses a frame format. The job of the HDLC layer is to ensure that data passed up to the next layer has been received exactly as transmitted (i.e. error free, without loss and in the correct order). Another important job is flow control, which ensures that data is transmitted only as fast as the receiver can receive it. There are two distinct HDLC implementations: HDLC NRM (see (SDLC) and HDLC Link Access Procedure Balanced (LAPB). Usually when referring to HDLC people mean LABP or some variation there of. HDLC LAPB is the Link Layer (Level 2 of the OSI model) that is usually used by X.25, the ITU (previously called the CCITT) standard for Packet Switched Networks.

Home Page: A Web site's introductory information page.

Hook Flash: A momentary depression of the switch hook to alert a PBX or switch, but not so long as to signal a disconnect. See flash

Hook switch: The place on the telephone where you lay your hand set or in the case of a portable telephone (not a cell phone) the on-off talk switch or button.

Hop: A term used in routing. A path to a destination on a network is a series of hops, through routers, away from the origin

Host: 1.A computer with direct access to the Internet. In a LAN, can be referred to as a host server. Contains Web server software and Web pages.

2. A mainframe or mini-computer using dumb terminals. IBM ES3090, IBM AS/400, DEC VAX, HP3000. Sometimes a large UNIX computer installed in a particular manner that might mimic the mainframe/mini dumb terminal network architecture.

HTML: Hypertext Markup Language used to produce Web pages. It is a method of presenting information where selected words can be expanded to provide other information about or related to the word.

Hub: A device connected to several other devices. In ARCnet, a hub is used to connect several computers together. In a message handling service, a hub is used for the transfer of messages across the network. These commonly use RJ45 connectors.

Hunt Group: A pool of phone lines organized together for a single application. The routing of incoming calls to members of the hunt group may be controlled in various ways. On simple systems calls may be routed via a single pilot number to the next available member. On complex ACD systems, the routing of calls may be controlled by more sophisticated algorithms.

IDE: Integrated Drive Electronics, The common method for connecting a Hard Disk Drive to a PC or other computing device. IDE Drives have the controller for the drive integrated onto the drive.

IEEE: Institute of Electrical and Electronics Engineer

IEEE 1394: Firewire is a high-speed, serial input/output bus for computer peripherals and consumer electronics, capable of transfer speeds of up to 400 megabits per second. * PRO: fastest external input/output bus available; supports up to 63 devices at once; optimal for bandwidth-hungry devices such as digital video cameras and external storage devices. * CON: not as widely implemented as Universal Serial Bus; needs fast CPU

Internet: An open, global network of interconnected private, commercial, educational and governmental computer networks which utilize a common communications protocol, TCP/IP.

Intranet: A closed, and sometimes widely dispersed network or wide area network (WAN) of interconnected computer networks, E-mail and Web servers which use the TCP/IP network protocol to communicate.

Inband Signaling: The exchange of signaling information for a call inside the voice path of a call. For example, the digits of the desired phone number for an outbound call might be passed as DTMF digits with in the voice path. Likewise, ANI/DNIS digits might be passed as DTMF digits in the voice path of an inbound call.

IP: Internet Protocol, See TCP/IP, Other common usage is that of an IP address is a set of numbers( assigned by your ISP to give a name to your machine when you connect to the internet.

ISDN: Integrated Services Digital Network combines voice and digital network services through a single medium, making it possible to offer digital data services as well as voice connections. ISDN comes in two interfaces, Basic Rate Interface (BRI) and Primary Rate Interface (PRI). In ISDN 23B+D the one D channel is out of band signaling. In T-1, signaling is handled in-band using robbed bit signaling. Increasingly, 23B+D is the preferred way of getting T-1 service since out of band signaling is richer (delivers more information like ANI and DNIS) and is more reliable than in-band signaling on the older T-1. This is a digital telephony standard. Two types of service are typically supported. Basic Rate Interface (BRI) supports two 64kbps B channels as well as one D channel for signaling. Primary Rate Service (PRI) supports 23 64kbps B channels for voice/data, and one D channel for signaling.

Isochronous In information technology, isochronous (from the Greek "equal" and "time"; pronounced "eye-SAH-krun-us") pertains to processes that require timing coordination to be successful, such as voice and digital video transmission. A sound or picture going from a peripheral computer device or across a network into a computer or television set needs to arrive at close to the same rate of data flow as the source. In feeding digital image data from a peripheral device (such as a video camera) to a display mechanism within a computer, isochronous data transfer ensures that data flows continuously and at a steady rate in close timing with the ability of the display mechanism to receive and display the image data. Isochronous can be distinguished from asynchronous, which pertains to processes that proceed independently of each other until a dependent process has to "interrupt" the other process, and synchronous, which pertains to processes in which one process has to wait on the completion of an event in another process before continuing.

Isochronous burst transmission: In a data network where the information-bearer channel rate is higher than the input data signaling rate, transmission performed by interrupting, at controlled intervals, the data stream being transmitted. Note 1: Isochronous burst transmission enables communication between data terminal equipment (DTE) and data networks that operate at dissimilar data signaling rates, such as when the information-bearer channel rate is higher than the DTE output data signaling rate. Note 2: The binary digits are transferred at the information-bearer channel rate. The transfer is interrupted at intervals in order to produce the required average data signaling rate. Note 3: The interruption is always for an integral number of unit intervals. (188) Note 4: Isochronous burst transmission has particular application where envelopes are being transferred between data circuit-terminating equipment (DCE) and only the bytes contained within the envelopes are being transferred between the DCE and the DTE. Synonyms burst isochronous (deprecated) , interrupted isochronous transmission.

ISP: Internet Service Provider. An organization that provides Internet access, connections and gateway services.

IVR: Interactive Voice Response. A CT caller-to-database application interface that allows a caller to access target information using a touch-tone(tm) phone. Callers can also leave information into a repository for processing, retrieve documents from a Web server or Fax-on-demand system for example.

JTAPI: Java Telephony Application Programming Interface was developed by JavaSoft, IBM, Intel, Lucent, Nortel and Novell with lead effort by Sun Microsystems. JTAPI is the standard telephony application programming interface for computer telephone applications under Java. JTAPI provides the definition for a set of reusable telephone call control objects. With it one gets application portability across platforms and implementations.

Java: A programming language developed by Sun Microsystems and derived from C, used to create mobile agents. Mobile agents can be in the form of applets which simulate a client/server architecture over the World Wide Web or the IP network (LAN/WAN), as opposed to current browser/Web-server interactivity which is essentially RPC based. Mobile agents like JAVA and M0 can free up host server resources by moving some computations and application processing to the client, leaving the host to serve up files, data and other mobile agents. Java can be deployed to create reusable objects called Java Beans in a true thin or light client architecture. Mobile agents differ from CGI in that CGI is a server-based process script, and responds to calls made to it by the browser (or terminal). API calls from the browser are still RPC-based, although they use fewer system resources than CGI. CGI can be scripted in Perl or Visual Basic. They can be compiled (faster) or non-compiled. Some Java Rapid Application Development environments include Symantec Cafe and Microsoft Visual J++.

JavaScript: JavaScript is a scripting language developed by Netscape that can interact with HTML source code. Although it shares many of the features and structures of the full Java language, it was developed independently. This scripting language (originally called LiveScript) developed by Netscape Communications for use with the Navigator browser. JavaScript code forms part of the HTML page and can be used for example to respond to user actions such as button clicks or to run processes locally or validate data. JavaScript is endorsed by a number of software companies and is an open language that anyone can use without purchasing a license. It is supported by recent browsers from Netscape and Microsoft, though Internet Explorer supports only a subset, which Microsoft calls Jscript.

JDK: The Java Development Kit created by Sun Microsystems.

KBPS: Kilobits per second. A measure of digital information transmission rates. One kilobit equals one thousand bits of information.

LAN: Local Area Network. A data communications network designed to interconnect personal computers, workstations, mini computers, file servers and other communications and computing devices with a localized environment.

LAPB Link Access Procedure Balanced is a bit-oriented synchronous protocol that provides complete data transparency in a full-duplex point-to-point operation. It supports a peer-to-peer link in that neither end of the link plays the role of the permanent master station. HDLC NRM (also known as SDLC), on the other hand, has a permanent primary station with one or more secondary stations.

Layer: Communication networks for computers may be organized as a set of more or less independent protocols, each in a different layer (also called level). The lowest layer governs direct host-to-host communication between the hardware at different hosts; the highest consists of user applications. Each layer builds on the layer beneath it. For each layer, programs at different hosts use protocols appropriate to the layer to communicate with each other. TCP/IP has five layers of protocols; OSI has seven. The advantages of different layers of protocols is that the methods of passing information from one layer to another are specified clearly as part of the protocol suite, and changes within a protocol layer are prevented from affecting the other layers. This greatly simplifies the task of designing and maintaining communication programs.

LDAP: Lightweight Directory Access Protocol, This protocol provides access for management and browser applications that provide read/write interactive access to the X.500 Directory.

LED: Light Emitting Diode, These are small devices used on PC hardware which can be illuminated. Many hardware cards may provide LEDs to signal information which can help diagnose problems. The field notes for all telephony/voice cards will include any LEDs which are available.

Line: A phone line.

Line Protocol: The protocol used on a phone line between the telephony system and the switch to provide call setup/breakdown/signaling. Examples include loopstart, groundstart, E&M WinkStart, and DID.

Line Type: A data structure used in the EWF to identify the capabilities of one or more phone lines.

Little-endian: A format for storage or transmission of binary data in which the least significant byte (bit) comes first. See also: big-endian.

Local Loop: Traditional view of physical plant/wiring network between the telephone company's CO and the subscriber/customer. In a PBX environment, the local loop/trunk is between Telco equipment and subscriber/customer premise equipment. Local Loop T-1/ISDN usually refers to the Front Bone. This is the network the Telco provides to permit subscriber access to the Back Bone (usually a much larger bandwidth network such as T-3, OC-48, etc.).

Loopback: Also known as loopback transfer. Loopback is when two phone lines are connected internally within the telephony system. This mechanism may be used to allow a caller to be transferred on systems which do not have a transfer capability. It has the disadvantage of requiring that the telephony system hold both phone lines while the two parties communicate.

Loopstart: A common line protocol used on analog phone lines.

MAC: Media Access Control, MAC address, The hardware address of a device connected to a shared media.

Malware: “Malicious software”; a generic term covering a range of software programs and types of programs designed to attack, degrade or prevent the intended use of an ICT or network. Types of malware can include viruses, worms, Trojans, malicious active content and denial of service attacks. In the case of invasion of privacy for the purposes of fraud or the theft of identity, software that passively observes the use of a computer is also malware (“spyware”).

Mbps: Mega bits per second. One thousand times KBPS.

Microcode: is the lowest-level instructions that directly control a microprocessor. A single machine-language instruction typically translates into several microcode instructions. Second, In modern PC microprocessors, the microcode is hardwired and can't be modified. Some RISC designer's go one step further by completely eliminating the microcode level so that machine instructions directly control the processor. This is the way computers worked before the advent of microcode. At the other end of the spectrum, some mainframe and minicomputer architecture utilize programmable microcode. In this case, the microcode is stored in EEPROM, which can be modified. This is called microprogramming the instructions. Be aware the some people will draw the boundary line between software/hardware at the microcode level and consider it synonym for firmware.

MIPS: Million instructions processed per second is a measure of processor compute power. See FLOPS. Also a registered tradename of a RISC processor manufacturer.

MAPI: Mail Application Programming Interface. A Microsoft technology standard for e-mail API.

Modem: Modulate/Demodulate A piece of equipment that connects a computer to an analog communications transmission line, typically a plain old telephone line (POTS). The modem translates digital information by manipulating an analogue carrier (sine) wave from the POTS and changes that carrier signal in concert with the data it is sending. See Baud. A 28,800 bit per second modem is actually a 2400 baud modem with advanced coding such that 12 bits are impressed on each baud.

MOS: Mean Opinion Scale is a rating system for sound quality over a transmission medium. Usually in reference to telephone or radio communications. The metric is scaled between 0 and 5, with 4.5+ being the widely accepted commercially viable rating over the PSTN.

Mosaic: The first of three publicly available, commercial Web browser.


Multiplex: A data routing and branching capability between multiple sources and recipients communicating amongst each other in real time.

Multiplexer: Combines multiple signals for simultaneous transmission.

MUD: Multi-User Dungeon, Adventure, role playing games, or simulations played on the Internet. Devotees call them "text-based virtual reality adventures." The games can feature fantasy combat, booby traps and magic. Players interact in real time and can change the "world" in the game as they play it.

MVIP: Multi-Vendor Integration Protocol. An open architecture for CT development.

NAK: Negative Acknowledgment, Response to the receipt of either a corrupted or unexpected packet of information.

Network: A collection of distributed computers which share data and information through interconnected lines of communication. A computer network is a data communications system which interconnects computer systems at various different sites. A network may be composed of any combination of LANs, MANs or WANs.

NTFS: "New Technology File System" designed in 1993 for Windows NT, 2000, XP is a high-performance and self-healing file system proprietary to Windows XP 2000 NT, which supports file-level security, compression and auditing. It also supports large volumes and powerful storage solution such as RAID. The most important new feature of NTFS is the ability to encrypt files and folders to protect your sensitive data.

Object: A catalogued sequence of highly predictable and reusable software code that describes a predefined event or process. One or more same or different objects that can be used together, in sequence or concurrently to provide functionality to a superset of code or programming.

ODBC: Part of Microsoft's Windows Open Services Architecture (WOSA) which describes a strategic interface for accessing data in a heterogeneous environment of relational and non-relational database management systems. Based on the Call-Level Interface (CLI) specification of the SQL Access Group (SAG), ODBC provides a vendor-neutral method of accessing data from a variety of data repositories.

On-hook/Off-hook: A traditional telephony term that describes a telephone handset that is on-hook or in its cradle. It is off-hook when it is lifted from the cradle. An original I/O system for telephony.

OSI: Open Systems Interconnect reference model developed by ISO. It is used to describe the flow of data between the physical connection to the network and the end-user application. This is the best known and most widely used to describe networking environments. The 7 layers of the OSI Reference Model include: Application, Presentation, Session, Transport, Network, Data Link, and Physical. Between two computers that are interacting, there exists a like-layer, virtual communication path.

The OSI layers are 7 Application (Application Compatibility), 6 Presentation (Data interpretation), 5 Session (Remote actions), 4 Transport (End-to-End Reliability), 3 Network (Destination Addressing), 2 Link (Media access & framing) and 1 Physical (Electrical Interconnection).

OPS: Off Premise Station, A family of protocols used on T1 digital lines which emulate standard loopstart signaling. OPS lines are often the only way to get transfer capabilities on T1 lines. There are several flavors of OPS protocols.

Orphan Call: An inbound call with no application to receive it. For example, if you do not have any inbound applications installed any inbound calls will be orphan calls. These calls will just ring until the caller gives up or the PBX/ACD forwards them.

Packet: The unit of data sent across a network. "Packet" a generic term used to describe unit of data at all levels of the protocol stack, but it is most correctly used to describe application data units.

PAM: Pulse Amplitude Modulation is a process which represents a continuous analog signal with a series of discrete analog samples. This is the basis of PCM and T-1.

Party Line: When multiple entities are connected to a single phone line. Traditionally this referred to multiple phones sharing a single connection to the local phone company. Typically this refers to connecting multiple telephony cards to a single phone line. For example, a CPI FAX card may be "party lined" to a VBX/100 telephony card to provide shared access to a single phone connection.

PDU Protocol Data Unit, a generic term for a communication protocol packet.

PING : Packet InterNet Groper, A program used to test ratability of destinations by sending them an ICMP echo request and waiting for a reply. The term is used as a verb: "Ping host X to see if it is up!"

PBX: Private branch exchange is analogous to the Telco's CO, but is owned and operated by someone other than the Telco. Provides the same service as CO but on a smaller scale and for a specific organization.

PCM: Pulse Code Modulation is the most common method of encoding (quantizing) an analog voice signal into a digital (binary) bit stream. Standard G711 describes this method of companding. PCM merely involves sampling and quantizing the input waveform. Narrow-band speech is typically band-limited to 4 kHz and sampled at 8 kHz. If linear quantization is used then to give good quality speech around twelve bits per sample are needed, giving a bit rate of 96 kbits/s. This bit rate can be reduced by using non-uniform quantization of the samples. In speech coding an approximation to a logarithmic quantizer is often used. Such quantizer give a signal to noise ratio which is almost constant over a wide range of input levels, and at a rate of eight bits/sample (or 64 kbits/s) give a reconstructed signal which is almost indistinguishable from the original. Such logarithmic quantizer were standardized in the 1960's, and are still widely used today. In America u-law companding is the standard, while in Europe the slightly different A-law compression is used. They have the advantages of low complexity and delay with high quality reproduced speech, but require a relatively high bit rate and have a high susceptibility to channel errors.

PEB: PCM to Expansion Bus from Dialogic which is used for large system development. The PEB defines an interface between the telephone network and the processing/system platform resources.

Perl: A language used for writing scripts that pass a CGI request from the Web server to run a gateway program.

Pilot Number: A single phone number which is used to route calls to a number of destinations within a hunt group. Often this type of routing is done on an ACD switch.

PPP: Point-to-Point Protocol, The Point-to-Point Protocol, defined in RFC 1661, provides a method for transmitting packets over serial point-to-point links. There are many other RFCs which define extensions to the basic protocol.

POP: Post Office Protocol and Point Of Presence. Post Office Protocol (POP) A protocol designed to allow single user hosts to read electronic mail from a server. Version 3, the most recent and most widely used, is defined in RFC 1725.

Port: This is a term which may have a variety of meanings in different contexts. To the Voice Subsystem this refers to a software and/or hardware entity which provides services to a phone lines. These services include voice, Text To Speech, Voice Recognition, FAX, pulse detection, and DTMF detection/generation.

POTS: Plain Old Telephone Service, This term is used in the telephony world to indicate a standard analog phone line. This is differentiated from specialized phones which take advantage of proprietary features of the local PBX/ACD. An example of such a feature is a telephone display which might show the name and phone number of the calling party. Analog phone connections normally use POTS connections. Most telephony system emulates a standard phone and call go onhook/offhook, dial, and other standard abilities, but may not be able to take advantage of some proprietary features of the local switch.

PL/SQL: The proprietary version of ANSI SQL (see SQL) developed, used and promoted by ORACLE Corp.

Poisson: Generally referred to as a mathematical formula devised by French mathematician S. D. Poisson. Further developed by E. C. Molina of AT&T for predicting call traffic distribution over telephone trunk lines.

POPs: Points-of-Presence. An interlinked group of modems, routers and other computer equipment, located in a particular city or metropolitan area, that allows a nearby subscriber to access the Internet through a local telephone call or using a short distance permanent data circuit.

Predictive Dialer: A system that intelligently makes and queues up calls based on the response and processing time required by a tele-operator to manage a script or questionnaire. It increases efficiency by dialing phone numbers at a certain rate based on the predictive algorithm and filling the pipe so as to keep call agents fed with live connections.

Proxy: The technique in which one machine, usually a router, answers ARP requests intended for another machine. By "faking" its identity, the router accepts responsibility for routing packets to the "real" destination. Proxy ARP allows a site to use a single IP address with two physical networks. Subnetting would normally be a better solution.

PRI: Primary Rate Interface, ISDN trunk which provides 23 B channels of 64kbps voice and one D channel for signaling.

Preview Dialer: Part of an automatic dialing application that allows on-screen preview of the number/record being dialed prior to actual dialing process. Timed Preview temporally spaces dialing events according to a pre-set schedule.

Primary Rate: The ISDN equivalent of a T-1 circuit. Contains 23 bearer channels Interface and one data channel in North America. Commonly referred to as 23B+D. This is enterprise level ISDN and highly desirable for CT applications.

Progressive Dialer: An automatic, dumb dialing application that gives on-screen view of the number/record dialed and connected.

Prompts: The prompts (or voice prompts) are the sets of files needed to control the speaking of objects such as dates, numbers, currency amounts, and phone numbers. Each Language (such as American English, Italian, American Spanish, etc.) must provide its own prompt set.

Protocol: A formal description of message formats and the rules two or more machines must follow in order to exchange such messages.

PSTN: Is the public switched telephone network and refers to the local Telco and its network.

PVC: Permanent Virtual Connections are established between DSUs for duplexed data transmission. Can be associated with MODEM, Frame Relay, X.25, ISDN, T-1/E-1, T-3, OC-48, VSAT, ATM and other networks.

Public Network: The phone system available to the public (as opposed to a private network used internally within a local company). National regulations typically control many aspects of connecting to the Public Network to guarantee computability across all vendor equipment, to ensure safety, and to prevent damage to the network.

Pulse Signaling: A method of providing digits to the phone switch. This method is also sometimes known as rotary dialing, as older phones would generate these pulses by rotating the phone dial across a set of electrical contacts. Pulse signaling has been widely replaced by DTMF signaling in the USA, but is still in wide use in many countries of the world.

QOS: Quality of service, a rating system for phone connections.

QNX: A proprietary, real time operating system based on micro kernel architecture for imbedded, network and PC systems.

RBOC: Regional Bell Operating Company, When AT&T broke up it, due to divestiture in 1983, it created 7 regional companies. Each regional company had two Bell Operating Companies separated its regional offices into separate local carrier service companies. Each company became known as a Regional Bell Operating Company, RBOC. They are: Ameritech; NYNEX, Bell Atlantic, BellSouth, Southwestern Bell, Pacific Telesis, and US West.

RFC: Internet Requests for Comments, The Internet Request For Comments (or RFC) documents are the written definitions of the protocols and policies of the Internet.

Relational Database: A database that is organized and accessed according to relationships between data items.

RISC: Reduced instruction set computer based on VLSI (very large scale integration) where a faster processor clock cycle is implemented with smaller instructions to increase performance.

RingNoAnswer: When a call fails after several rings without being answered.

RJ11: A standard connector for providing a single analog phone line.

RJ14: A standard connector which provides two analog phone lines on a single connector. Physically the RJ14 is the same as the RJ11 except that two of the three available pairs of wires are used.

RJ45: A standard telephony connector often used to connect a PC to a Ethernet Hub.

RJ48C: A standard telephony connector often used for T1 connections.

Robbed Bit Signaling: Typically uses the A & B bits which are sent on each side of the T-1 termination, and are buried in the voice data of each voice channel in the T-1 circuit. Hence the term as the bits are stolen from the voice data. Since the bits are stolen so infrequently voice quality is not overly compromised, but the available signaling combinations are limited to ringing, hang up, wink and pulse digit dialing.

ROM: is an acronym for Read Only Memory. see: EEPOM for more details about basic memory types.

Rotary Phone: The providing of phone number digits to the phone switch using pulses generated by the rotating of the phone dial across electrical contacts. This type of signaling has been mostly replaced by DTMF signaling in this country, but is still in wide use around the world.

Router: A device that receives and transmits data packets between segments in a network or different networks.

RPC: Remote Procedure Call is a command that is made from a station to another station to perform a transaction or computation within specifications and where the results are returned to the station making the call. Often confused with client/server.

RS232 RS-232 is the serial interface that has been around as a standard for decades as an electrical interface between Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE) such as modems or DSUs. It appears under different incarnations such as RS-232C, RS-232D, V.24, V.28 or V.10 but essentially all these interfaces are interoperable. RS-232 is used for asynchronous data transfer as well as synchronous links such as SDLC, HDLC, Frame Relay and X.25.

RSVP: Resource reSerVation Protocol dynamically reserves network resources such as bandwidth or buffers to guarantee quality of service for telephony and other multimedia applications on the Internet.

RTFM Read The F**ing Manual, this is a term used for people that continually ask foolish questions that can easily be answered, if they only read the instruction manual.

RTP/RTCP: Real-time Transport Protocol/Real-time Transport Control Protocol. Companion protocols where RTP includes packet sequencing information and time stamps for synchronizing data streams, and where RTCP provides feedback on current network conditions, allowing the telephony software to switch compression algorithms in response to degraded connections.

RTS Request to Send is a status line associated with a transmission control such as RS232.

S.100: An ECTF system architecture that describes a standard for computer telephony platforms and networks.

SDLC Synchronous Data Link Control was invented by IBM to replace the older Bisynchronous protocol for wide area connections between IBM equipment. A variation of the ISO HDLC protocol called HDLC Normal Response Mode (NRM) is essentially the same as SDLC. SDLC is not a peer to peer protocol like HDLC, Frame Relay or X.25. An SDLC network is made up of a primary station that controls all communications, and one or more secondary stations. Where multiple secondary are connected to a single primary, this is known as a multi-point or multi-drop network.

SEC: Samsung Electronics Corporation ( Korea )

Service Bureau: An enterprise which maintains large sets of equipment which they use to sell specialized services to others. For example, a FAX Service Bureau might provide FAX Back Service to others who do not want to support their own FAX hardware.

SCSA: Signal Computing System Architecture. An open standard highly promoted by Dialogic for specifying the interfaces for PC-based CTI applications.

SCSI: Small Computer System Interface, is a computer interface used to connect various device that follow this standard to a PC or other computing device.

SPOX: A proprietary micro kernel operating system for DSP architectures used in Dialogic Antares speech recognition cards.

SS7: Signaling System 7. A Telco network for providing signaling information regarding calls on the network (PSTN).

Server: Software that allows a computer to offer a service to another computer but in the client/server world not an application computation or RPC service. Other computers contact the server program by means of matching client software. In addition, such term means the computer in which server software runs.

SLIP/PPP: Serial Link Internet Protocol/ Point-to-Point Protocol. The standardized description of a software program used to transmit data on asynchronous lines.

SNAFU: Situation Normal All F*cked Up, A term adopted from the US military and used when people continually feel completely helpless and can find no way to make a program or hardware device function or when the state of a project is FUBAR. Often miss spelled as "snafoo" by persons that do not understand the actual origin of the word. Usage: "This is another SNAFU!"

SONET: Synchronous Optical NETwork, SONET is an international standard for high-speed data communications over fiber-optic media. The transmission rates range from 51.84Mbps to 2.5Gbps.

SQL: Pronounced Ess-Cue-El, not sequel, and due to evolution, the letters no longer mean anything, although confusion exists. In the mid 1970s, IBM Research Laboratory developed a language to implement the relational database management system model. The prototype language was called SEQUEL for Structured English Query Language and was the application programming interface to their embryonic relational database called System R. In 1977, a new design prototype emerged which was called SEQUEL/2; but, the name was later changed to SQL. This is the source of the common belief that SQL is an acronym for Structured Query Language and is pronounced sequel. The first company to market SQL relational database management systems was Relational Software, now known as Oracle Corporation. SQL is the accepted standard for data definition, data manipulation, data management, access protection, and transaction control of relational databases. It uses tables indexes, keys, rows, and columns to identify storage locations. Many types of applications use SQL statements to access data. Examples include ad hoc query facilities, decision support applications, report generation utilities, and online transaction processing systems such as relational Web environments.

STA: Samsung Telecommunications America

Supervised Transfer: A transfer where one completes the transfer by waiting for the transfer party to answer the call. When as state such as RingNoAnswer occurs the supervisor will transfer the caller to a pre-desginated location. This is usually an AA or VM system.

Synchronous Synchronous communication, In synchronous communications, data is not sent in individual bytes, but as frames of large data blocks. Frame sizes vary from a few bytes through 1500 bytes for Ethernet or 4096 bytes for most Frame Relay systems. The clock is embedded in the data stream encoding, or provided on separate clock lines such that the sender and receiver are always in synchronization during a frame transmission.

T.120: An ITU/IEEE standard for data conferencing.

T1: A digital transmission link with a capacity of 1.544 Mbps. The T1 (trunk) digital lines were developed to replace the analog lines that interconnected the local telephone offices (CO, central office) in the USA. Can normally handle 24 voice conversations each digitized at 64kbps. Typically used for connections of networks across remote distances (Wide Area Networks or WAN). Ideal for Internet connectivity, though not as desirable for CT as PRI ISDN. Same as DEA in Canada

T2: A digital transmission link with a capacity of 6.312 Mbps. Typically used for connections of networks across remote distances (Wide Area Networks or WAN).

T3: A term for a digital carrier facility used to transmit a DS-3 formatted digital signal at 44.746 megabits per second.

T4: A term for a digital carrier facility used to transmit a DS-4 digital signal at 274.760 megabits per second. Can handle 4032 voice conversations each digitized at 64kbps. Typically used for connections of networks across remote distances (Wide Area Networks or WAN).

TAPI: Telephony Application Programming Interface. A Microsoft and Intel API technology standard. TAPI is changing regularly to meet integration needs. Its current release is TAPI 2.0. TAPI simplifies the process of writing a telephone application that works with a wide variety of modems and other devices supported by TAPI drivers. In contrast to TSAPI, TAPI places the emphasis on the Windows operating environment, while TSAPI operates at the Network Operating System level.

TCP: Transmission Control Protocol, Protocol used on Internet and IP open architecture to transfer data across a network or wide area network.

TCP/IP: Transmission Control Protocol/Internet Protocol. A compilation of network and transport level protocols that allow computers with different architectures and operating system software to communicate with other computers on the Internet. The IP transmits the data packets from the sender to the recipient in the shortest time possible. The TCP manages the flow and ensures the data is correct.

TCP/IP has the following five layers: 5 Application (Application messages or streams), 4 Transport TCP layer (datagrams UDP or segment TCP), 3 Internet (IP datagrams), 2 Data-Link (Network Interface framing) and 1 Network Hardware (Electrical Interconnection).

      1. The Application layer passes a stream of bytes to the Transport layer on the source computer. At the destination, The application on the destination computer receives a stream of bytes, just as if it were directly connected to the application on the source computer.
      2. The Transport/TCP layer divides the stream into TCP segments, adds a header with a sequence number for that segment, and passes the segment to the Internet (IP) layer. The checksum is computed. At the destination, The TCP layer computes a checksum for the TCP header and data. If the computed checksum does not match the checksum transmitted in the header, the TCP layer discards the segment. If the checksum is correct and the segment is in the correct sequence, the TCP layer sends an acknowledgment to the source computer. The TCP layer discards the TCP header and passes the bytes in the segment just received to the application.
      3. The IP layer creates a packet with a data portion containing the TCP segment. The IP layer adds a packet header containing source and destination IP addresses. The IP layer also determines the physical address of the destination computer or intermediate computer on the way to the destination host. It passes the packet and the physical address to the Data-Link layer. The checksum is computed again. At the destination, the IP layer checks the IP packet header. If the checksum contained in the header does not match the checksum computed by the IP layer, it discards the packet. If the checksums match, the IP layer discards the IP packet header and passes the TCP segment to the TCP layer. The TCP layer checks the sequence number to determine whether the segment is the correct segment in the sequence.
      4. The Data-Link layer transmits the IP packet in the data portion of a data-link frame to the destination computer. If the destination is an intermediate computer, then Step 3 happens again until the final destination is reached. At the destination computer, the Data-Link layer discards the data-link header and passes the IP packet to the IP layer.
      5. Network hardware performs the actual transmission from computer to computer. Information passes down from the Data-link layer and back up to the Data-link layer of another computer in the network. This may not be the final destination.

Telnet: Telnet is the Internet standard protocol for remote terminal connection service. It is defined in RFC 854 and extended with options by many other RFCs.

Terminus: The bondary point at which a Phone Company's lines end and the customers wiring begin.

TIFF: Tagged Information File Format, A standard for representing compressed FAX images. The standard defines different types of TIFF files. In addition, vendor specific differences often exist between files used by different systems.

Telnet: A tool used to log into other computers connected to the Internet. It is typically used access public servers, such as library, university and other databases.

Third Party Call Control: Also referred to as Telecom Server on a LAN means a call control server, (i.e. a server running Dialogic CT-Connect, or a DEC Integrated Telecommunications AlphaServer or Mitel MediaPath Server) which is installed as another node on the LAN. This server is equipped with hardware components and software elements necessary to deliver CTI links and/or solutions to the workgroup. The telecom server connects directly to the PSTN or to the PBX to handle all calls coming into this group, and connects directly to the desktop client to deliver those calls.

Tip & Ring: The traditional telephony indication of (+)/ground and (-)/positive in electrical circuits. Standard telephone connections require 2 wires. For historical reasons relating to the manual plugs used by operations for switching, these 2 wires are known as Tip and Ring.

TouchTone: see DTMF

TSAPI: Telephony Server Access Protocol Interface, An API developed by Novell and AT&T for control of telephony features. AT&T and Novell created the TSAPI standard to help pass controls between the PBX and a Novell server. AT&T describes TSAPI as "standards-based API for call control, call/device monitoring and query, call routing, device/system maintenance capabilities, and basic directory services." In contrast to TAPI, the control is at the NOS layer, not at the Windows operating system layer.

Trunk: In telephony jargon a trunk typically referred to telephony connections between switches (as opposed to between the switch and the telephone). This term becomes less clear when IVR equipment terminates the phone line. In general, the term trunk and phone line some what interchangeably. For more details see Details of Trunk Lines

TTS: Text To Speech, The ability to translate text into spoken voice.

Twisted Pair: Standard, inexpensive cabling commonly used for telephony applications. Typically it consists of two copper wires twisted around each other to reduce outside interference.

µLAW: A method of companding (or compressing) digitized voice. With µLAW, 12 bits of audio are compressed to 8 bits, while A-LAW compresses 14 bits of audio to 8 bits of PCM. The µLAW method is used in the United States, Canada, and Japan. The other method, A-LAW, is used in Europe and much of the rest of the world. Commonly pronounced MU-LAW. From the Greek letter "µ."

UDP: User Datagram Protocol is defined to make available a datagram mode of packet-switched computer communication in the environment of an interconnected set of computer networks. This protocol assumes that the Internet Protocol (IP) [1] is used as the underlying protocol. This protocol provides a procedure for application programs to send messages to other programs with a minimum of protocol mechanism. The protocol is transaction oriented, and delivery and duplicate protection are not guaranteed. UDP can be thought of as Unsolicited Data Packets. Applications requiring ordered reliable delivery of streams of data should use the Transmission Control Protocol (TCP).

Under-run: When the local PC cannot provide data fast enough to service a phone line. For example, if voice data cannot be passed out to a voice card fast enough the remote caller would hear a gap in the spoken voice prompts. Typically under-run errors occur because the local PC system has insufficient CPU real-time available.

URL: Uniform Resource Locators, are the Internet's all-purpose reference tools. They act much like addresses, not only to actual data, but to any definable resource on the Internet, including the results of application commands. URLs are available for newsgroups on UseNet, Gopher servers, Telnet connections, WAIS server files, and World Wide Web server files (the most common usage in HTML). Any link from an HTML document to another file or application is written in the form of a URL.

USB: Universal Serial Bus, or USB, is a computer standard designed to eliminate the guesswork in connecting peripherals to your PC. Currently, the USB Specification, Revision 2.0, covers three speeds 480 Mbps, 12 Mbps, and 1.5 Mbps. The term "Hi-Speed USB" refers to just the 480 Mbps portion of the USB Specification. We now use the term "USB" to refer to the 12Mbps and 1.5Mbps speeds.

VOIP Voice Over IP is any scheme to transmit and receive voice signals over the internet using internet protocol. Generally, voice is compressed using a Codec and then transmitted to the destination using UDP protocol where it is decompressed using the same Codec.

VM: Voice Mail, A specialized voice processing application which is dedicated to accepting, controlling, and routing voice messages.

VPN: Virtual Private Network. Typically, a network within a network where the host network (i.e. the Internet) supports a secure private network via such technologies as point-to-point tunneling protocol (PPTP).

VTG: The Vocaltec Telephony Gateway is a telephony server that provides telephone access to another VTG elsewhere via the Internet. VTGs are initially implemented in pairs for point-to-point access. VTGs can accept an analogue device (i.e. telephone set, modem, fax) directly, or it can work behind (inside the customer premise) the PBX to permit access to another gateway from the customer's OEM telephone. A VTG can be configured to allow anyone with a PIN to access it from anywhere (i.e. the local PSTN) to make a high quality, duplexed telephone call to someone else's telephone via a second or numerous other gateways.

Web or WWW: World Wide Web. A network of computer servers that uses a special communications protocol to link different servers throughout the Internet, and permits communication of graphics, video and sound.

Web Sites or Web Pages: A site located on the Web, written in HTML. See Home Page above.

Web Server: The computer system that runs Web software, used to create custom Web Sites, Web Pages and Home Pages. Also, the Web software itself.

Wink: In general a wink is a type of signal sent across a phone line between two pieces of equipment. On an analog, loopstart phone line a wink consists of a momentary dropping of loop current. PBXs often use such winks to provide hang-up supervision, signaling to the telephony system that the remote caller has dropped the call and that the line can be freed.

Windows NT: A 32-bit, true pre-emptive multi-tasking and multi threading operating system for RISC and CISC-based servers, PCs and workstations. Originally co-developed with IBM and called OS/2, Windows NT supports POSIX I and II APIs, DOS and 16 bit Windows, as well as 32-bit Windows 95 applications. The operating system consists of the executive, the hardware abstraction layer, the Kernel, and the API layer which support the various applications. Windows NT supports C2-level security which allows multiple DOS, Win16 and Win32 sessions each within their own specially created virtual machine. Crash of one application occurs only within its virtual machine and does not affect other applications running or the data they contain. Windows NT runs on Digital Alpha AXP RISC CPUs, MIPS R CPUs, PowerPC and Intel CPUs. Windows NT is reported to run best on AXP and MIPS CPUs and Intel Pentium Pro CPUs.

X.25: A data communications interface specification developed to describe how data passes into and out of public data communications networks. The CCITT and ISO approved protocol suite defines protocol layers 1 through 3.

ZCS: Zero Code Suppression, A method used to ensure sufficient one's density on a T1 connection. On T1 circuits one must guarantee a certain density of voltage transitions to maintain clock synchronization between the sender and receiver. ZCS if used to insert a code containing a one when ever a string of too many zero's is detected. Obviously both the sender and receiver must agree that ZCS is being used to make sure that the original bit pattern is restored.

Zerofill: An activity used by a transmitting fax machine which can send data faster than the recipient can process it. To give time for the recipient to catch up, the transmitter pads or zerofills the outbound transmission.