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Glossary - A
Access services are specific sets of information transfer capabilities that are furnished to users at telecommunications network POTs, or points-of-termination. They provide access to network transport services. One example would be subscriber access lines, which involve the connection between a network POT (more commonly recognised in this case as a Network Interface NI) and a local exchange carrier switching system. Another example could be trunks between local exchange carrier switching system and interexchange carrier points-of-presence (The POT at the POP is identified as the point of interface POI). To enable end-to-end connections there must be originating and terminating access service.
Access Tandem (AT)
Access Tandem is a LEC switching system. AT performs concentration and distribution functions for inter- LATA traffic (orignating or terminating).
Access Point (AP)
Base station in a wireless LAN. Typically, access points are stand-alone devices that plug into a server or Ethernet hub. Like the mobile phone system, users can roam around with their mobile devices being passed from one access point to another.
Automatic call distribution.
Access coordination fee.
These convey destination information, for example, a called 4-digit extension number or central office code, and - if and when required - an area code and serving IXC carrier code. Signals may be generated by a switching system or station equipment.
Asymmetric Digital Subscriber Line or Digital Subscriber Line, most commonly transfers data back and foth between a subscribers premises. It does this by 'piggybacking' onto existing infrastructure, generally a standard BT analogue telephone line. It sometimes utilises existing mains power supply cabling or also proprietary or satellite cabled networks. Data transfer is conducted by using a high-frequency carrier. This enables the un-interrupted working of the existing service used for the vehicle transmission. There are two components to the data transfer - transmission and reception. In ADSL, one (often transmission) is carried out at a slower-rate than the other.
Alternate mark inve.
Advanced Mobile Phone Service (AMPS). The standard AMPS for analog cellular telephones operates in the 800 MHz band and uses frequency spacing and frequency-modulated transmission to separate user transmissions.
A wireless modem that is designed for analog cellular phones.
Analog Carrier System
A transmission system that compensates for analog medium impairments using repeaters, which also produce output signals (linear-scaled version of input signals). This system can carry speech, video, data and supervisory signals. However, they best suit for speech signals.
An analog signal exists as a continuous electrical signal varying in direct correlation to either an impressed phenomenon, stimulus, or an event bearing intelligence. Sound waves and their electrical analogs have two distinct characteristics, loudness (amplitude) and pitch. Analog signals can assume any infinte number of amplitude values or states within a specified range and in analogous to or in accordance with an impressed stimulus. The pitch refers to the number of times per second the signal swings between low and high amplitudes (in other words, its frequency).
Automatic number identification.
Anonymous call rejection
Where a caller has withheld CLI, this service acts to prevent calls from being put through or connected.
American National Standards Institute. ANSI is a membership organization that was founded in 1918 to coordinate the development of U.S. voluntary national standards in both pubic and private sectors. It is the U.S. member body to IEC and ISO. IT standards pertain to the following; programming languages, EDI, telecommunications and physical properties of cartridges, diskettes, and magnetic tapes.
Asynchronous balanced mode.
Alternate space inversion.
Asynchronous Transfer Mode (ATM)
Asynchronous Transfer Mode is a low delay, broad-bandwidth, packet-like (cell relay) multiplexing and switching technique. Essentially it is connection oriented, although its evisioned to support all services. ATM networks either accept or reject connections dependent on a given user's average and peak bandwidth requirements. This provides both an efficient and flexible service for compressed video, LAN-to-LAN and other applications involving variable bit rate traffic.
See Asynchronous Transfer Mode
These are smart boxes which automatically dial the prefix needed to route calls to the specified CPS operator. Thye are installed at the customer's home.
Automatic Call Distribution
ACD enables the efficient direction and management of large numbers of incoming calls to specified terminals or departments within an organization.
Total cost of production averaged over total quantity produced.