Quick Eagle Networks DL3800E - Manual (Page 152)

G-6 DL3800E Inverse Multiplexer User’s Guide — July 9, 2001
G
DSU Loopback
A DSU loopback is intended to include as much of the customer data
communications circuitry in the looped-back path as possible. The signal passes
from the remote unit into the local unit as far as the DSU. This test loops the
received network signal back to the network.
DSU/CSU (Data Service Unit/Channel Service Units)
The pair of communications devices that connect an in-house line to an
external digital circuit. At the customer's end of the telephone connection, the
DSU/CSU takes data from terminals and computers, encodes it, and transmits
it down the link. At the receive end, another DSU/CSU equalizes the received
signal, filters it, and decodes it for interpretation by the end-user.
DSX-1 (Digital Signal Cross Connect Level 1)
Parameters set used when DS-1 signals are cross connected.
DTE (Data Terminal Equipment)
Terminal equipment connected to the DSU and used for communication over
digital networks. May be a terminal, computer, printer or multiplexer.
DTE loopback
An EIA-232-D signal which indicates that the DTE is ready for operation.
DTR (Data Terminal Ready)
Signal from DTE to DSU/CSU.
E
EER (Excessive Error Rate)
Determined by counting the number of T1/T3 code violations during a time
interval.
EFS (Error Free Seconds)
Occurs when a second is free of CRC-6 violations or Out of Frame (OOF) events
or one or more BPV or OOF events.
EIA (Electronic Industries Association)
An organization which sets data communication industry standards.
encoding/decoding
The process of reformatting information into a format suitable for
transmission, and then recovering it after transmission.