Digital Link DL600E, Руководство пользователя

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Glossary
G-7
multidrop
Ñ A communications arrangement where multiple devices share a
common transmission channel, though only one may transmit at a time.
N
NI (Network Interface)
Ñ The point of demarcation between the customer
premises and the carrier's network, usually drawn at the network connector on
the rear panel of the Digital Link access device.
P
parity bit
Ñ An additional, non-informational bit appended to a group of bits
indicating that the number of ÒonesÓ in the bits group is odd or even.
parity check
Ñ A process of error checking using the parity bit.
plug
Ñ A male connector designed to Þt into a particular socket.
polarity
Ñ Any condition where there are two opposing charges, such as posi-
tive and negative.
port
Ñ The physical point of access into a computer, network or other elec-
tronic device.
protocol
Ñ A formal set of rules governing the format, timing, sequencing and
error control of exchanged messages on a data network.
Q
QRW
is a pseudo random signal which may catch problems not exposed by
other test patterns. The
DSU/CSU
transmits a
QRW
pattern to the
E1
network,
the remote system loops it back to the
DSU/CSU
which monitors the signal
for
QRW
bit errors.
R
RAI (Received Alarm Indication)
Ñ An
RAI
occurs when one end detects a
loss of frame alignment condition and sends a remote end alarm signal bit to
the other end.
RD (Receive Data)
Ñ A data port signal.
receiver
Ñ The receiver synchronizes the framing pattern, separates the frame
bits from the payload data and monitors for frame errors in 64K mode. It
achieves frame synchronization within 5msec
(ANSI T1.410-1992
Section
8.2).