Verilink Access Manager 2000 (896-502037-001) Product Manual User Manual
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Access Manager 2000 Manual
A-5
CRC-6 Regeneration
A mode in which the CRC-6 is recalculated for incoming data before it
is retransmitted. In this mode, any incoming CRC-6 errors are not
propagated (although the data may be corrupted).
CSU
See Channel Service Unit.
CSU Slot Number
The plug-in slot location of a CSU in a multiline or dual-line shelf.
CTS
Clear To Send.
Current
The amount of electrical charge flowing past a specified circuit point
per unit of time. See Ampere (A).
Current Status
An indication of current line and/or circuit element status, including
CSU signal state and Payload Loopback (PLB) status.
CV-L
See Code Violation - Line.
CV-P
See Code Violation - Path.
Cyclic Redundancy
Check (1)
A check sum indicator, which is based on the remainder of a
polynomial calculation performed on the transmitted data, that is used
to verify, with some fixed probability of correctness, whether that data
was corrupted.
Cyclic Redundancy
Check (2)
This code is embedded in the ESF format and derived from a
mathematical calculation performed on the data bits of an Extended
Superframe (ESF) field (all 4632 bits) to obtain a six-bit Cyclic
Redundancy Checksum (CRC-6) code for those data bits. The near-end
DTE or ESF CSU transmits these six bits in the appropriate CRC-6
positions of the next ESF field across the facilities to the far-end DTE
or ESF CSU. The CRC-6 code is recalculated by the far-end CSU
(based on the current ESF field received) and then compared to the
CRC-6 that was originally transmitted. If the two CRC-6s match, it is
highly probable that the ESF field arrived without error. If the CRC-6s
do not match, one or more errors may have occurred during
transmission of that particular ESF field. The CRC-6 code is capable of
detecting 98.4% of all ESFs containing transmission errors. These error
events are logged into an internal register within the ESF CSU and may
be recalled on a last 24-hour basis from the local or remote CSU
through the ESF Data Link using Access Manager 2000.
Term
Definition