WPIM-DI Local Management Guide
D-1
APPENDIX D
WAN TERMS AND ACRONYMS
This appendix provides definitions for WAN terms and acronyms.
AMI
Alternate Mark Inversion, line coding used with both E-1
and T-1. A digital 1 is encoded as a “mark” (pulse) and a
0 is encoded as a “space.” The marks alternate polarity.
ANSI
American National Standards Institute, the US member
of the ISO.
Bearer (B)
Channel
A 64 Kbps channel used with BRI and PRI ISDN
services.
Bipolar
Violation
The occurrence of two successive pulses of the same
polarity in a bipolar signal.
B8ZS
Binary 8-Zero Substitution, line coding utilized with ESF
(Expanded Super Frame). Insures the ones density
requirement for digital T-carrier facilities in the public
network, while allowing 64 Kbps clear data per channel.
This encoding method is not supported by some Telcos.
BRI
Basic Rate Interface, minimum rate ISDN subscriber
interface, provides 2 B + 1 D channels (two 64 Kbps “B”
(Bearer) channels and one 16 Kbps “D” (Data) signaling
channel for a total of 144 Kbps).
BRIM
Cabletron Systems Bridge Router Interface Module.
Expands the physical connectivity of a host device.
CRC
Cyclic Redundancy Check, an algorithm or process used
to identify corrupted packets in the transmission link.
CSU
Channel Service Unit, a device that terminates the local
loop/digital channel on a customer’s (DSU) premises.
The CSU connects to a DSX-1 interface on the CPE.