Nortel Passport 4400, Using Manual, Page: 124 / 144

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206906-D Rev 00 4.2
committed information rate
See CIR.
common channel signaling
See CCS.
Compander/Companding
Companding is a combination of the words “compressing” and “expanding”.
It relates to a process of compressing digital signals prior to transmission, then
restoring them to their original condition at the receiving end. The
µ
-Law
(mu-Law) type is commonly used in North America and Japan; a-Law is the
European version, as defined in G.711.
CPU reset
In a CPU reset operation, the Passport 4400 CPU is restarted, and the
committed application code and configuration data are loaded from Flash into
DRAM.
CRC
Cyclic Redundancy Check. A computational means to ensure the accuracy of
frames transmitted between devices in a frame relay network.
CRC-4
A cyclic redundancy check pattern used on an E1 line. When enabled, the E1
Voice Module generates and monitors for the CRC algorithm carried on bit 1
of Time Slot 0 of an E1 frame.
CSU
Channel Service Unit. In industry usage, a device located between the digital
line coming from the Central Office and the local data communications
equipment. It provides line equalization and conditioning functions suitable
for meeting the requirements of the service provider.
current reset
In a current reset operation, the Passport 4400 CPU is restarted, diagnostics
are run, and the committed application code and configuration data are loaded
from Flash into DRAM.