| Glossary: A |
| A and Z direction |
For a two-point circuit, one end is A and the other end is Z. For a multipoint circuit, the master station is A and the remote stations or terminals are Z. |
| AAL |
ATM Adaptation Layer |
| ABR |
Available Bit Rate |
| Acceptance mask |
A collection of thresholds assigned to circuit performance parameters. When used during circuit testing, it automatically reports whether a particular performance parameter has failed. |
| ACNA |
Access Carrier Name Abbreviation |
| Action set |
A set of instructions used to control the parsing of responses or variables in a dialog. |
| Add-drop multiplexer (ADM) |
A SONET multiplexer capable of extracting or inserting lower-rate signals from a higher-rate multiplexed signal without completely demultiplexing the signal |
| ADSL |
Asymmetric Digital Subscriber Line |
| Advanced Intelligent Network (AIN) |
A telecommunications network in which complex call processing, routing, and network management are provided by means of centralized database at a few points, rather than from a speed signaling network carrying information on call setup to an individual switch |
| AF |
Autoframed. See Autoframe. |
| AID |
Access Identifier |
| AIS |
See Alarm Indication Signal |
| Alarm Indication Signal (AIS) |
An unframed All Ones signal that replaces the normal traffic signal when a maintenance alarm indication has been activated. Also called a blue alarm. |
| AIS-CI |
Alarm Indication Signal–Customer Installation. See Alarm Indication Signal. |
| AIX® |
|
| Advanced Interactive Executive (AIX) |
The computer operating system for several Hekimian systems, including REACT 2001™, REACT 2000, and PM Integrator™. |
| All ones code |
A signal stream containing 15,360 or less zeros in one second. When a device loses synchronization, it sends an all ones code to keep the network up. It also sends this code to tell the network there is a transmission problem. |
| Alternate mark inversion (AMI) |
A line-coding format for T1 lines where successive marks alternate between positive and negative polarity. The marks are equal in amplitude. A space designates zero amplitude. |
| American Standard Code for Information Interchange (ASCII) |
A code with seven information signals plus one parity check signal. It is useful for interworking between computers. |
| AMOS |
Access Mechanized Order System |
| Analog |
In communications, transmission employing variable and continuous waveforms to represent information values. |
| Analog signal |
A nominally continuous electrical signal that varies in amplitude or frequency |
| ANSI |
American National Standards Institute |
| AOR |
Area of Responsibility |
| API |
Applications Programming Interface |
| Asynchronous error measurement |
A measurement that detects error events referenced by the system's time clock. |
| Asynchronous transfer mode (ATM) |
A transmission mode in which information is organized in cells (packets). It is asynchronous in the sense that the recurrence of cells depends upon the required or instantaneous bit rate. |
| Asynchronous transmission |
Transmission in which time intervals between transmitted characters may be of unequal length. Transmission is controlled by start and stop bits at the beginning and end of each character. |
| ATAF |
ATM Test Access Function |
| Attenuation |
Amount of signal loss in a transmission. Usually measured in decibels. High attenuation can be caused by poor connections, defective connector hardware, excessively long lines, or ambient temperatures |
| Attribute |
An occurrence that can be detected and reported by Hekimian's 3246 T1 Line Performance Monitor (TLPM) or 3248 T1 Service Performance Monitor (TSPM). |
| ATU-C |
ADSL Transmission Unit-Central |
| ATU-R |
ADSL Transmission Unit-Remote |
| Autoframe |
A process which determines the framing on the digital circuit and reports the framing format. |
| AWS |
ADSL Workstation |
| AXP |
Alpha Processor |
