Digital Link DL600E, Руководство пользователя

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G-2 DL600E E1 Data Multiplexer UserÕs Guide
circuit
Ñ Generally referring to a transmission medium connecting two or
more electronic devices.
clear channel
Ñ A characteristic of a transmission path or digital circuit in
which the full bandwidth is available to the user. The phone company does
not use any portion of the bandwidth for framing or control bits.
clock
Ñ An oscillator-generated signal providing a timing reference for a
transmission link; used to control timing functions such as sampling interval,
signaling rate and duration of signal elements.
code conversion
ÑThe process of changing the bit grouping for a character in
one code into the corresponding bit grouping for the character in another.
Code Violation (CV)
Ñ A code violation occurs when the ones bit is not repre-
sented with the opposite signal of the previous ones bit.
communications port (Comm Port)
Ñ The electrical interface between a unit
and the operatorÕs terminal. Operator commands and responses can be com-
municated through the Comm Port.
connector
Ñ A physical interface, such as
DA15
or
RS232-C
, typically with
male or female components.
CPE (Customer Premises Equipment)
Ñ Equipment that interfaces the tele-
phone network and physically resides at the user's location.
CRC (Cyclic Redundancy Check)
ÑA link-level error checking feature used
when additional protection is needed against simulation of the frame align-
ment signal and/or when an enhanced error monitoring capability is needed.
A CRC
calculation is performed and four frame bits are used to store it over
the content of the frame. The
CRC
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 incremented.
CSU (Channel Service Unit)
Ñ The
CPE
used to terminate a digital circuit at
the customer site. It performs certain line-conditioning functions, ensures net-
work compliance to
FCC
rules and responds to loopback commands. It
ensures proper ones density in the bit stream and performs bipolar violation
correction. A
DSU
and
CSU
are often in the same unit, called a
DSU/CSU
.
CTS (Clear to Send)
Ñ A signal issued by the DSU to indicate it is connected
to the digital network and is ready to accept data.
CV (Code Violation)
Ñ Occurs when the ones bit is not represented with the
opposite signal of the previous ones bit.