Glossary-13160-A2-GB22-10 December 1996
Glossary
AIS Alarm Indication Signal. A signal transmitted instead of the normal signal to
continue 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.
AMI Alternate Mark Inversion. A line encoding technique and a bipolar return-to-zero
signal.
Async T
erminal This feature allows a DSU/CSU to be controlled from an asynchronous (async)
terminal. When this feature is enabled, the async terminal menus and displays
emulate the DCP without being limited to the 2-line LCD display.
Auxiliary Backplane An 8-slot backplane that fits over one half of the open section of the 3000 Series
Carrier
. This is a passive assembly that provides interconnect capability between
3151 CSUs and 3161 DSU/CSUs and provides all interface connectors.
AW G American Wire Gauge.
BES
Bursty Error Seconds. A second in which more than one, but less than 320 CRC6
error events, have occurred.
BPV Bipolar Violation. A modified bipolar signaling method in which a control code is
inserted into the original data format.
B8ZS Bipolar with 8 Zero Substitution.
CRC Cyclic Redundancy Check. A method of error detection.
CSU Channel Service Unit. Protects the T1 line from damage and regenerates the
T1 signal.
DCE Data Communications Equipment.
DSU Data Service Unit. Data communications equipment which transmits digital data
over a private line. Also used for limited distance communications over the PSTN
when a high-speed modem is not needed.
DS0 Digital Signal level 0. A signal of worldwide standard speed for PCM digital voice
channels running at 64 kbps.
DS1 Digital Signal level 1. A signal of 1.544 Mbps in North America.
DSX-1 Digital Signal Cross Connect level 1. An interconnection point for terminals,
multiplexers and transmission facilities.
DTE Data Terminal Equipment.
DTMF Dual Tone Multifrequency. The basis of operation for a pushbutton telephone.
D4
The transmission standard that specifies 12 frames as a superframe that is used for
frame synchronization and to locate signaling bits.
