GL-1

9161-A2-GH30-30 April 1998
Glossary
Alarm Indication Signal. An all ones signal transmitted to maintain transmission continuity
and to indicate to the receiving terminal that a transmission fault exists at either the
transmitting terminal or upstream of the transmitting signal. Sometimes referred to as Blue
Alarm.
Alternate Mark Inversion. A line coding technique used to accommodate the ones density
requirements of E1 or T1 lines.
Application Module.
American Wire Gauge. An indication of wire size. The heavier the gauge, the lower the
AWG number, and the lower the impedance.
Bursty Error Seconds. A second in which more than one, but less than 320 CRC6 error
events have occurred.
Bipolar Violation. In a bipolar signal, a one (mark, pulse) which has the same polarity as its
predecessor.
Bipolar with Eight Zero Substitution. Encoding scheme for transmitting clear channel
signals over a T1 line.
Communications port. A computer’s serial communications port used to transmit to and
receive data from a modem. The modem connects directly to this port.
Device software that sets specific operating parameters for the device. Sometimes
referred to as straps.
Cyclic Redundancy Check. A mathematical method of confirming the integrity of received
digital data.
Controlled Slip Seconds. A period in which a frame was added or deleted because of a
variance in timing.
Channel Service Unit. A device that connects service user equipment or a DSU to the local
digital telephone loop.
Data Communications Equipment. The equipment that provides the functions required to
establish, maintain, and end a connection. It also provides the signal conversion required
for communication between the DTE and the network.
Direct Inward Dialing.
Dial Pulse Originating.
Dial Pulse Terminating.
Data Service Unit. Data communications equipment that provides timing, signal
regeneration, and an interface to data terminal equipment. A subrate DSU/CSU is normally
referred to as a DSU.
Digital Signal Cross Connect level 1. An interconnection point for terminals, multiplexers
and transmission facilities.
Digital Signal level 0 (zero). A 64 kbps digital telecommunications signal or channel.
AIS
AMI
APM
AWG
BES
BPV
B8ZS
COM port
configuration option
CRC
CSS
CSU
DCE
DID
DPO
DPT
DSU
DSX-1
DS0