Quick Eagle Networks DL3800E - Manual (Page 150)

G-4 DL3800E Inverse Multiplexer User’s Guide — July 9, 2001
G
connector
A physical interface, such as DB-15 or RS-232-C, typically with male or female
components.
CPE (Customer Premises Equipment)
Equipment that interfaces the telephone network and physically resides at
your location.
CRC (Cyclic Redundancy Check)
An error checking scheme used to check the received data. The CRC bits
within the framing are calculated using the contents of the frame. The
calculation is performed again when the frame is received and the CRC values
are compared. If they do not match, the frame is considered bad and the CRC
statistic is incremental. Performance checking is done by both the carrier and
the customer without causing any interference with the T-1 traffic.
CSU (Channel Service Unit)
The CPE used to terminate a digital circuit at the customer site. The CSU
performs certain line-conditioning functions, ensures network compliance to
FCC rules and responds to loopback commands. It ensures proper ones density
in the bit stream and performs bipolar violation correction. The DSU and CSU
are often in the same unit.
CTS (Clear to Send)
A signal issued by the DSU to indicate it is connected to the digital network
and is ready to accept data.
CV (Code Violation)
Any code violation.
D
D4
Framing format for T1 transmission that places 12 T1 frames into a superframe.
In ESF (a newer framing format) frames consist of 24 bits instead of the
previous standard 12 bits as in D4 format.
DACS (Digital Access Cross-Connect Switch)
A digital switching device for routing and switching T1 lines and DS-0 portions
of lines among multiple T1 ports. DACS performs all the functions of a normal
switch, except that connections are typically set up in advance of a call, not
together with a call, as in most, normal low-bandwidth communications
systems (e.g. voice-band voice and data). A DACS is in essence a manual T-1
switch.