Tele-Communication (Telecom) Terms Glossary and Dictionary - A A & B Bit A & B Bit is used in digital environments to convey signaling information. A bit equal to one generally corresponds to loop current flowing in an analog environment; A bit value of zero corresponds to no loop Current, i.e. to no connection. Other signals are made by changing bit values: for example, a flash-hook is sent by briefly setting the A bit to zero. A Links A Links, also known as SS7 access links, connect an end office or signal point to a mated pair of signal transfer points. They may also connect signal transfer points and signal control points at the regional level with the A-links assigned in a quad arrangement. A&B Bit Signaling A&B Bit Signaling, also called 24th channel signaling, is a procedure used in T1 transmission facilities in which each of the 24Â T1 subchannels devotes 1 bit of every sixth frame to the carrying of supervisory signaling information. On T1 lines that use Extended SuperFrame(ESF) framing, the signaling bits are robbed from the 6th, 12th, 18th, and 24th frame, resulting in "ABCD" signaling bits. ABAM cable ABAM cable refers to a type of T1 cable. This cable was a 22 gauge, 100 ohm insulated, twisted pair. ABAM cable is no longer available, but you can easily find cable that meets the technical requirements. Abandoned Call Abandoned Call is a call in which the call originator disconnects or cancels the call after a connection has been made, but before the call is established. Abandonment Abandonment refers to the network replacement of a connect signal with an on-hook signal (network) prior to receiving a CI (customer installation) answer signal. Abandonment is the only way to end an unanswered call attempt. Abbreviated Address Abbreviated Address is an address that has fewer characters than the full address, usually for special communications and other services or for certain users. Examples of abbreviated addresses are (A) a four-digit telephone number for a user calling another user connected to the same switching exchange, and (B) message addresses that have only the addressee name and station code or number. Abbreviated Address Calling Abbreviated Address Calling is a calling that enables a user to employ an address having fewer characters than the full address when initiating a call. Communications network users may be allowed to designate a given number of abbreviated address codes. The allocation of the abbreviated address codes to a destination or group of destinations may be changed as required, by means of a suitable procedure. Abbreviated Dialing Abbreviated Dialing is a telephone feature (synonym speed dialing ) that (A) permits the user to dial fewer digits to access a network than are required under the nominal numbering plan, and (B) is limited to a subscriber-selected set of frequently dialed numbers. ABCD Signaling ABCD signaling is a 4-bit telephony line signaling coding in which each letter represents 1 of the 4 bits. This often is associated with CAS or robbed-bit signaling on a T1 or E1 telephony trunk. ABCD Signaling Bits ABCD Signaling Bits, also refered as ABCD Bits, are 4-bits telephony line signaling coding in which each letter represents 1 of the 4 bits. The implementations of ABCD signaling are different in E1 and T1 digital trunks. On E1, ABCD bit values may be used to signal an incoming call, disconnect, seize and so on, They are closely analogous to the A and Bits commonly used on T-1 digital trunks. On E1, there are 32 channels (time-slots) in contrast to 24 channels on T-1, hence the faster bit rate of 2.048 MHz versus 1.544 MHz for T-1. On E1, channels 0 and 16 are used to carry the ABCD bits and synchronization (framing) bits; hence only 30 channels are available for audio conversations. On T-1 digital trunks, the ABCD Signaling Bits implements the robbed bit signaling. ABCD Tones ABCD Tones are simply additional DTMF tones that may be used in any way the standard (0-9) tones are used. The ABCD Tones are used in the U.S. Military telephone network (Aoto Von), in some Automatic Call Distributor (ACD) systems, for control messages in some PBX systems, and in some amateur radio auto-patches. ABDN: Attendant Blocking of Directory Number Attendant Blocking of Directory Number (ABDN) is a feature of telephone service enables the attendant to block a DN (Directory Number) for a telephone from receiving to making calls. This is particularly useful when a caller dials the attendant DN and requests an external (long distance) call. If the caller chooses to disconnect until the attendant successfully places the call, the requesting DN becomes idle and can receive or make calls. Therefore, the requesting DN could be busy when the attendant establishes the requested call. Absent Subscriber Service Absent Subscriber Service is a telephone service provided by local telephone carriers to customers who will be away for a period of time and want to stop the service without losing their telephone number . The calls to the subscriber will be intercepted by a live operator or a machine and a message will be delivered. When the customers come back, they will get their old number. But in the meantime, while they are away, they pay less money per month than they would for normal phone service. Absolute Delay Absolute delay refers to the following: 1. The time interval or phase difference between transmission and reception of a signal. 2. The total time between the instant a bit enters the network and the instant a corresponding bit exists the network Absorption Band Absorption Band is a range of wavelengths (or, equivalently, frequencies) in the electromagnetic spectrum within which electromagnetic energy is absorbed by a substance. When the absorbing substance is a polyatomic gas, an absorption band actually is composed of a group of discrete absorption lines which appear to overlap. Each line is associated with a particular mode of vibration or rotation induced in a gas molecule by the incident radiation. Absorption Coefficient Absorption coefficient is measure of the attenuation caused by absorption of energy that results from its passage through a medium. Absorption coefficients are usually expressed in units of reciprocal distance. The sum of the absorption coefficient and the scattering coefficient is the attenuation coefficient. Absorption Spectrum Absorption Spectrum is a diagram which shows the wavelengths of electromagnetic radiation absorbed by a material. The material could be a gas, a solute or a solid. An absorption spectrum is, in a sense, the inverse of an emission spectrum. AC/DC Ringing AC/DC Ringing refers to telephone ringing that use both ac and dc voltages and currents. AC: Access Code Access Code (AC) refers to a set of digits or numbers besides regular telephone number dialed on the telephone in order to access some telephone related services. For instance, some phone needs to dial 9 to "access outside line", some long distance carrier needs a special set of code to be connected, etc. ACA: Automatic Circuit Assurance Automatic Circuit Assurance (ACA) is a PBX feature that helps one to identify bad trunks. The PBX keeps records of calls of very short and very long duration. If these calls exceed a certain parameter, the attendant is notified. The logic is that a lot of very short calls or one very long call may snidest that a trunk is hung, broken or out of order, The attendant can then physically dial into that trunk and check it. ACB: Automatic Call Back Automatic Call Back (ACB) is a telephone feature that allows one to instruct the telephone system to retain the called and calling numbers, when encountering a busy situation, to reestablish the call when there is an available line. Access Attempt Access Attempt is the process by which one or more users interact with a telecommunications system to enable initiation of user information transfer. An access attempt begins with an issuance of an access request by an access originator and ends either in successful access or in access failure. Access Charge Access Charge is the charge or fees imposed by a communications service or telephone company for the use of its network. Access Failure Access Failure refers to an unsuccessful access in a telecommunications system that results in termination of an access attempt in any manner other than initiation of user information transfer between the intended source and destination (sink) within the specified maximum access time Access Group Access Group refers to a set of phones or terminals that have the same permission to access the phone system, computers and networks. Access Line Access Line refers to a transmission path that continuously connects a subscriber's premises to a switching center, common carrier operating center, or teleprocessing system. Access Link Access link is the local line connecting customer to the central office switch, giving access to a PSTN carrier who will provide the customer dial tone or private line communications services. The access link may be a T1 line, a DSL connection, a cable (CATV) network, a broadband wireless link, or a metro-Ethernet connection. Access Number Access Number refers to "dial-up Numbers" to access to an local Internet Service Provider. Access Protection Access Protection refers to the process or means to protect a telephone system local loop against possible outages and failures. Access Rate Access Rate refers to the maximum data transmission rate over the access link in a typical network like former AT&T hikes cable access rate. Account Code Account Code is a numeric code that must be entered to dial long distance numbers in some companies to control telephone billing.