Carrier Access Access Navigator user manual Identifier

Circuit	A character string assigned by the circuit vendor, which is useful when
Identifier	communicating with the vendor during the troubleshooting process.
Circuit	Basic switching process whereby a circuit between two users is opened on
Switching	demand and maintained for their exclusive use for the duration of the
	transmission.
Coding	CV. A transmission error detected by the difference between the transmitted and
Violation	the locally calculated bit-interleaved parity.
Community	String that defines an administrative relationship between SNMP entities.
Name
Crossconnect	A non-permanent, two-way signal connection using wire or fiber used to join
	two circuits together or to complete a signal path between a source and
	destination. A simple crossconnect might use copper wires on a punchdown
	block to complete a circuit between an incoming telephone line connected to one
	set of terminals and a desk phone connected to a second set of terminals. Patch
	cords and cables can also be used to make connections. Connections can also be
	made electronically using a Digital Crossconnect System.

CSU Attenuation

Adjusting output amplitude to meet the receiver requirements of the Channel Service Unit. CSUs are designed for long-distance operation and usually require additional signal attenuation when closer to the transmitter. Attenuation is measured in decibels (dB) and is usually selectable in fixed steps between 0 dB and -22.5 dB.

Customer	CPE. Items of telecommunications equipment, such as key systems, PBXs,
Premises	answering machines, and CSU/DSUs, which reside on the customer’s premises
Equipment	past the carrier’s network interface.
Cyclic	CRC. A technique for detecting transmission errors. A CRC indicator based on
Redundancy	the remainder of a polynomial calculation is performed on the transmitted data
Check	and inserted into the frame overhead. Another CRC is calculated for the received
	data and compared to the embedded CRC to check for transmission errors.
D4	D4 framing gets its name from AT&T corporation's D4-series channel banks. D4
	is used for T1 transmissions and contains 12 separate 193-bit frames combined
	to make a Super Frame (SF). Each frame contains one framing bit followed by
	the data for 24 channels (8 bits each). D4 also uses the framing bit to identify the
	channel bank and to synchronize the receiver to decode the robbed-bit signaling
	data carried by the least-significant bit of each DS0 channel.

Data Communi- cations Equipment

DCE. In the EIA/TIA 232E standard specification, the RS-232 interface is connected between Data Communications Equipment (DCE) and Data Terminal Equipment (DTE). The main difference between the DCE and the DTE is that pins two and three are reversed on the cable connector.