• Home
  • Telquest International - Telecom Glossary

Glossary of Telecom Terminology

Abbreviated Dialing

  • Also known as speed dialing, allows a list of frequently called numbers to be stored in system memory and accessed via a two- or three-digit code.

Account Code

  • Allows a station user to enter an account code that will be included in SMDR or Call Accounting reports to detail the record of calls made or received; codes can be forced, optional, or standard; they can be verifiable or not verifiable.

ACD / Call Management System

  • An automatic call distribution or call management system routes calls to groups of agents based on all agents spending an equal amount of time on calls. systems range from simple to elaborate and usually provide considerable report information on trunk line usage and agent activity. Standalone ACD systems typically are compatible with most telephone systems.

Add-On Conference

  • Allows station users to establish a three-party conference call while on an outside line call by adding another station or outside line.

Alarm Indication

  • The system supports either alarm lamps or alarm error code/message displays to be provided at the attendant's position to indicate problems or malfunctions in the system's operation.

Authorization Code (COS Override)

  • Allows certain station users, when visiting at another user's phone, to enter an authorization code to temporarily override that phone's Class of Service and allow users to make outside calls in accordance with their own Class of Service restrictions.

Auto Attendant

  • Allows incoming trunk calls to be answered by an automated attendant; a call could be a recorded greeting followed by transfer to a live station or attendant, or it could give the caller dialing instructions to reach certain users, departments, or a live attendant.

Auto Line Preference

  • Also referred to as Auto Line Selection, Idle Line Preference, or Prime Line Preference, this feature allows a user to be automatically connected to a central office trunk line when going off hook.

ARS - Auto Route Selection

  • Also known as Optimal Routing, routes calls over the public network based on the preferred (normally the least expensive) route available at the time the call is placed; Least Cost Routing, a similar feature, has been considered to be a more sophisticated version of this feature that also includes such enhancements as time of day/day of week routing patterns.

Automatic Busy Redial

  • Allows a user who has placed an outside call to a busy number to have the system redial the number (for multiple attempts) until the call is connected.

Automatic Hold Recall

  • Allows calls to be placed on hold and recalls the called party if there is no response to the call within a specified period of time.

Automatic Set Relocation

  • The ability to physically move a phone without losing any programming (such as speed dials, etc.)

Automatic Wakeup (Timed Reminder)

  • Allows users to enter a request for a call or signal to be generated by the system to their station at a specific time (for meeting reminder or similar application).

Background Music

  • Allows music to be heard through the speakerphone of the telephone.

Backup / Overflow Facility

  • Permits the attendant to have calls which are normally routed to that position sent instead to a backup or overflow station (or night service bell) during peak calling periods, or simply when the incoming call volume has exceeded a certain threshold level; can be automatic or controlled by the attendant.

Battery Back-up

Memory - Protects memory features (that is, the customer database) from a power loss by using a battery back-up.

System - Protects the entire system and keeps it fully operational in the event of a commercial power failure; feature may require only batteries and a battery charger, or it may require an uninterruptable power system.


  • Allows a specified number of station users who share a line appearance to simultaneously go off hook and actively bridge on the line; systems with this feature typically allow multiple stations to bridge on a trunk or feature appearance at one time; systems that allow one additional user to bridge would be classified as offering only the Privacy Release (Non-Privacy) feature.

Busy Override

  • Allows users to override a busy signal to break into an existing conversation; most systems offer this feature in conjunction with a warning tone that is given to both parties of the current conversation; some systems offer this feature with or without the use of the warning tone.

Call Accounting System

  • Used in conjunction with the Station Message Detail Recording (SMDR) feature to provide detailed records and to report on incoming and outgoing calls through the telephone system; Call Accounting adds calling charges to facilitate departmental billing, client billing, and verification of telephone company bills; standalone Call Accounting systems are typically compatible with most telephone systems that incorporate SMDR.

Call Coverage

  • Allows buttons to be shared or paired between users so that an unanswered call can be answered (covered) by the other user.

Call Duration

  • Alerts a station user when an outgoing call exceeds a preset time period as follows:

Signal - Generates an alerting tone to a station user.

Display - Sets an elapsed call timer for station users equipped with display telephones.

Call Forward

  • Enables users to forward calls to any other telephone extension; forwarding can be arranged for:

  • -Busy calls only

  • -No answer calls

  • -All calls

Fixed - Supports fixed forwarding to a preassigned location, such as a manager to a secretary; the call forward destination is normally flexible, allowing the station user to enter the number of the forward to destination, but some systems also provide fixed forwarding.

Override / Return - Allows forwarded calls to be overridden by another call and the forwarded call returned to the call forwarder's station; for example, a manager forwards a call to a secretary, but if the secretary receives an important call, she can override the forward condition and return that call to the manager.

;Off PremiseSupports off premise call forwarding; most systems support call forwarding only to other stations internal to the system, but some systems also support forwarding to off premise locations.

Call Park

  • Allows users to transfer calls to parking or orbit zones where the calls remain on hold until picked up at the same station or at a station at another location.

Call Park (with Recall)

  • An automatic function of some systems that recalls either the original station or the attendant to ensure that the caller is not forgotten when a call is placed in a Park location for an extended period of time.

Call Pickup (Directed, Group)

  • Directed call pickup enables any user to pick up a call ringing at an unattended station; group call pickup enables users to be members of a specific group, allowing any member of that group to dial an access code to pick up a call ringing at an unattended member's station.

Caller Identification

ICLID - InComing Line Information Database - The name of the person calling or the caller's telephone number displays on the phone's screen. Caller ID can be provided by the local phone company or the service provider.

ANI - Automatic Number Identification - When an incoming call is received over an ISDN trunk, the caller's telephone number, or ANI, is provided by the public telephone network to the PBX. While routing the call, the PBX sends the ANI to a computer application, and customer data related to the ANI can be displayed.

DNIS - Dialed Number Identification Service - While routing an incoming call, the PBX sends the telephone number dialed by the incoming caller to a computer application. Data relevant to this telephone number is displayed on the user's telephone screen or PC. DNIS differs from ANI and ICLID since DNIS represents the number a caller called, while ANI and ICLID represents the number a caller called from.

Camp-on / Call Waiting

  • Allows users to wait on a line when encountering a busy signal, called party is alerted by a tone when another party is waiting; at the completion of the initial call the waiting party is automatically connected to the called party.


  • Allows the user to set up a conference call with four or more parties which can be a mixture of internal and/or external parties and, generally, at least two of the parties can be outside trunk lines.

CCSA - Common Control Switching Arrangement

  • An arrangement in which switching for a private network is provided by one or more common control switching systems. Note: The switching systems may be shared by several private networks and also may be shared with the public telephone networks.

CAS - Centralized Attendant Service

  • Allows a system to serve as the location for the primary attendant(s), who can then answer incoming calls and route them over special trunks to the outlying branch offices; serves as an important feature for users with multiple sites in a fairly close geographical area; some systems can function as either the main or the branch location in such an operation, while others can only serve as a branch location

Centrex Compatibility

  • Indicates whether or not the system supports behind Centrex installation (that is, can Centrex lines be assigned buttons on proprietary keysets and do station users have the capability to generate a switchhook Flash, and access Centrex features?). If this functionality is noted as Standard (S), then no additional hardware or software is required; however, if this functionality is noted as Optional (O), then some additional hardware and/or software is necessary.

Computer Telephony Integration / TAPI - Telephone Application Programming Interface

  • Developed by Microsoft and Intel, is a set of functions that allows software developers to write telephony software applications for an individual PC. TAPI allows Windows applications programs to control telephony functions such as establishing, answering and terminating calls. Some companies have a proprietary version of TAPI.

COS - Class of Service

  • Enables the system administrator to restrict or allow access to specific features and calling privileges on individual phones by assigning different Class of Service codes.


  • Also known as self testing, allows the system to perform self diagnostic testing and alert the attendant or system administrator via alarm lamps or error code messages when a fault is detected.

Dial Pulse / DTMF (Dual-Tone MultiFrequency) Signaling

  • The system can accept touch-tone or rotary dial stations and outside trunk lines and convert one signaling mode to the other as required to process the calls.

Direct Group Calling

  • Allows users to call a group of stations such as a sales department by dialing a group code number.

Direct In Line

  • Allows specific central office trunk lines to be assigned to ring directly to a station or group of stations without being routed through the attendant position.

Directory Service

  • Gives the attendant access to an electronic directory of the system's station users, such that when a name is entered, the station number is displayed.

DID - Direct Inward Dial

  • Connects calls from the public network directly to the dialed extension without attendant assistance; most systems can add or delete digits as required to complete the call.

Distinctive Ringing

  • The system presents calls to the station user's telephone with different ringing patterns that identify the call as originating from an outside trunk line or an internal station, or as a callback, etc.

Do Not Disturb

  • Prohibits calls from terminating at a particular station.

Do Not Disturb (with Override)

  • Allows authorized users to override the Do Not Disturb feature and have their calls ring in to the station that is in Do Not Disturb mode.

Door Phone

  • Allows an intercom box or a combination intercom box/electronic door lock to be installed on an outside door and be directly connected to a specific station or to the system.

E911 - Enhanced 911

  • This feature transmits a caller's phone number and location to an Emergency System.

Executive Override of Privacy

  • Allows authorized users to override the privacy feature and join in an existing two-party conversation.

External Alerting Device

  • The system supports the connection of external bells, lights, or gongs that can be placed in special areas of the customer's premises to facilitate the handling of calls.

External Page Interface

  • Allows the system to be connected to an external loudspeaker paging system for one or more zones.

Flexible Station Numbering

  • Allows customers to establish their own numbering scheme for station numbers, feature access codes, and trunk access codes, as compared to some systems where these assignments are fixed in the system programming.

Handsfree Answerback on Intercom

  • Allows station users, normally those equipped with proprietary telephones, to answer incoming intercom calls in a handsfree mode (via an integral speaker), even though their telephone may not be equipped for full handsfree operation.

Healthcare Package

  • A special set of features specific to the healthcare professions, including medical centers, hospitals, and nursing homes; some systems offer separate packages for healthcare and lodging, while others may combine these two functions by offering only a few features that are commonly used by both areas.


  • Allows station users to put outside callers on hold so that they can answer or initiate another call.

Exclusive Hold - Only the station user who put the caller on hold can access the call.

System Hold - Any other station user with the same line appearance can pick up the call.


  • Or, manual line / house phone, allows a direct connection to be established to another station in the system, when a user goes off hook.

Hold Indication

  • Provides multi-line station users with an indication as to which holding line is the one that they placed on hold.

Incoming Call Group

  • Allows central office trunk lines to be assigned to ring directly into a group of stations without being routed through the attendant.


  • Routes incoming calls to unassigned station numbers or routes other misdialed calls to the attendant for handling

Internal Paging

  • Allows users to place page calls to certain groups of users or to all users on the system via the telephone set speaker.

ISDN Interface - Integrated Services Digital Network Interface 

  • -A switched network utilizing a digital connection to a central office to provide end-to-end digital connectivity and support both voice and non-voice services. The system can support a Primary Rate Interface (PRI) for ISDN connections to other systems, allowing 23 circuit-switched B bearer channels (64 Kbps each), plus one packet-switched D data channel (16 Kbps) to be carried over a single link.
  • -The system supports a Basic Rate Interface (BRI), an ISDN standard that allows two circuit-switched B bearer channels (64 Kbps each), plus one packet-switched D data channel (16 Kbps) to be carried over a single twisted pair. BRI can exist on the network side or the internal line side of a telephone system.

LCR - Least Cost Routing

  • Similar to Auto Route Selection (ARS), but generally a more complex offering that includes routing by time of day, day of week, and digit translation.

Lodging Package

  • A special set of features specific to the hotel/motel lodging industry.

Main/Satellite Service

  • -Allows multiple systems to be interconnected with special trunk circuits to facilitate common numbering plans and access codes; considerable feature transparency between systems is supported.
  • -A station user in one of the satellite systems, for example, can answer an incoming call and transfer that call to a station user in another satellite system just by performing the normal hookswitch/transfer and then dialing the extension number of the other user. An example of a typical application is several buildings in an office park or a college campus that are interconnected to appear as one large system.

Manual Signaling

  • Allows users to send a manual signal or intercom tone to another station user by pressing a button.

MW - Message Waiting

  • Allows callers to light a message waiting lamp to signal telephone users to contact another station user or the message center for messages; includes the following:

Attendant Station - Originated by an attendant to a station.

Station-Station - Originated by a station to another station.

Displayed Messages - Identifies displayed messages such as pre-programmed or personalized text messages that would appear on the other user's display phone; only available to station users who are equipped with display telephones.

Message Waiting Activation

  • Allows the attendant to activate the message waiting lamp or button indicator on a station set

Multiple Attendant Positions

  • The system can support more than one attendant position.

Multiple Trunk Groups - Allows central office trunk lines to be assigned to pools or groups in applications that require more than one central office trunk line for the same function


  • Alerts outside callers that they are on hold and still connected; an FM tuner can be plugged into the Music-on-Hold port for built-in synthesizer functionality.

Night Service

  • Allows central office trunk lines to be assigned to different ringing locations after normal business hours; includes the following:

Fixed Assignments - Fixed for specific telephone locations.

Flexible Assignments - Includes ringing a night bell that could then allow any station user to answer the call by dialing a special pickup code Off-Premise Extension: supports off-site stations, providing the same capabilities and features as on-site stations; normally applies to single-line sets.

On Hook Dialing

  • Allows station users to dial calls without lifting the handset.

Outgoing Call Restrictions

  • Allows the system to be programmed to restrict defined stations from making outgoing calls or only calls to specific locations.

Override/Busy Verification

  • The attendant can break into an existing station or trunk line call to verify that the facilities are actually in use or to announce an important call or emergency condition

Personalized Ringing

  • Allows station users to program personalized ringing tones to distinguish one ringing telephone from another.

Power Failure Transfer Phones

  • Allows certain central office trunk lines to be directly connected to certain telephones in the event of a system or commercial power failure.


  • Allows for all connections to be private, so that another user cannot accidentally or intentionally enter an existing conversation.

Privacy Release / Non-Privacy

  • Allows the station user to control whether the Privacy feature can be used and provides the flexibility to release the privacy feature to allow another station user with the same line appearance to join in on the conversation.

Private Line

  • Also known as personal lines; enables a trunk line to be assigned to a specific button that can only appear on certain telephones or that only a specified station user is allowed to access


  • An open, standards-based signaling protocol used for inter-PBX communications. Supported by most PBX vendors (unlike other PBX protocols, which have historically been proprietary), QSIG provides signaling and feature interoperability between PBX systems.

Recorded Messages

  • Allows the system to connect callers to a recorded announcement in conjunction with such features as Night Service, Station Hunting, Automatic Call Distribution, and Auto Wakeup.

Remote Access

  • Allows specified users to dial into the system from an outside location and be permitted access to system features and outside lines.

Repeat Last Number Dialed / Redial

  • Allows a user to redial the last number dialed by pressing a button or dialing an access code.

Ringing Line Preference

  • Provides one-step operation by allowing the user to answer the telephone without manually selecting the ringing line.

Saved Number Redial

  • Allows a user to dial a number and save it so that it can be redialed at a later time by pressing a button or dialing an access code.

Security Alarm Interface

  • Allows an alarm to be placed on a door and to be connected to the telephone system to be activated whenever the door is opened.

Series Calling

  • The attendant, upon receiving a call where the caller wants to talk to several stations in sequence, can initiate a series call so that when the first called party hangs up, the caller will automatically return to the attendant's position for establishment of the next call.

Station Hunting

  • Allows incoming calls to hunt through a group of assigned station users until an available station is located; can utilize the following formats:

Circular Hunting - Begins with the called station number and continues through all members until an idle station is found.

Terminal Hunting - Begins with the called station and ends with the last station in the group.

Secretarial Hunting - Routes calls to a busy hunt group, or several busy hunt groups to a common secretarial phone for answering.

Master / Pilot Number Hunting - Begins when the caller dials the Pilot or Master Number assigned to the group.

Distributed or UCD-type Hunting - Begins progressively, such as at the station following the last one to receive a call.

SMDR - Station Message Detail Recording

  • Enables reports to be generated that provide time, duration, and number dialed; incoming and outgoing calls can usually be tracked.

Station Queuing / Trunk Queuing With Callback

  • Allows station users who encounter a busy station or line to put themselves in queue and go on hook; the user receives a callback when the line or busy station becomes available.

System Programming / Administration

  • The attendant's position can also be used for system programming and administration functions when removed from call processing mode and placed into programming mode.

T1 Digital Trunk Interface

  • The system supports a direct 24-channel T1 digital trunk interface.

Tenant Service

  • Allows more than one organization (tenant) to share the same system; through programming, each tenant can be restricted to its own CO trunks, attendant consoles, and extension links; incoming calls are directed to the appropriate tenant.

Tie Trunk

  • Enables inter-system tie trunk links to be added to the telephone system, for private connections between two or more user systems.

Toll Restriction

  • Allows the user to restrict specified telephones from making long distance toll calls:

0/1 - Specifies calls blocked on all 0+ and 1+ calls.

Area/Office Code - Specifies calls blocked to certain area code and/or office code combinations.

Allow/Deny Lists - Specifies lists of allowed numbers or codes and denied numbers or codes.

Toll Restriction Override

  • Allows authorized users to temporarily override toll restriction assignments on a specific phone:

By Code - Specifies that authorized users can temporarily override toll restriction by dialing an authorization code.

By System Abbreviated Dialing - Specifies that authorized users can temporarily override toll restriction by accessing specific Abbreviated Dialing numbers.

Traffic Measurement

  • Enables the system to generate utilization reports on such statistics as number of calls and duration of calls placed on different lines or the frequency that all lines are busy; also generates reports on the usage of certain other features.

Trunk-to-Trunk Connection

  • Also known as Unsupervised Conference; allows a user to establish a connection between two outside lines, where the user is not required to remain in the conversation.

Unified Messaging

  • Provides access to voice, fax, and e-mail on a PC via the telephone.

Use Indication

  • Provides multi-line station users with an indication as to which line is the one that they are utilizing at that time.

Voice Synthesizer

  • Allows the system to provide synthesized electronic voice prompts or messages for use in conjunction with system programming or the message waiting feature

Voicemail Interface

  • Allows the system to be connected to an external voice mail/messaging system.

Voicemail / Messaging System

  • -Supports a voice mail system to receive and store messages from outside or internal callers and to send messages to other internal users.
  • -VM/MS systems normally connect to the telephone system via station or trunk ports, support multiple users, and store messages on tapes or disks. These systems are also available in standalone versions that are compatible with many telephone systems.
  • -Typical systems are integrated with the telephone system to alert a user to a stored message via a message waiting indicator or other user alert method. More sophisticated product offerings also support networking to facilitate intercommunication among systems installed at multiple sites.

VoIP - Voice over Internet Protocol

  • Allows the transmission of packetized and compressed voice, along with fax and data information, over the Internet or a corporate intranet. This can reduce the need for more expensive leased public switched telephone network (PSTN) tie trunk facilities, resulting in cost savings for the customer.

Volume Control

Speaker/Ringer - Allows users with proprietary telephones to adjust the volume for the incoming call ringer and the telephone set's speaker.

Microphone - Allows users with proprietary telephones to adjust the outgoing volume for their microphone.