User`s guide

Glossary G-7

multidropÑA communications arrangement where multiple devices share a

common transmission channel, though only one may transmit at a time.

NI (Network Interface)ÑThe 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.

parity bitÑAn 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 checkÑA process of error checking using the parity bit.

plugÑA male connector designed to Þt into a particular socket.

polarityÑAny condition where there are two opposing charges, such as posi-

tive and negative.

portÑThe physical point of access into a computer, network or other elec-

tronic device.

protocolÑA formal set of rules governing the format, timing, sequencing and

error control of exchanged messages on a data network.

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.

RAI (Received Alarm Indication)ÑAn 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)ÑA data port signal.

receiverÑThe 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).