ADTRAN 4200659L1 - Manual (Page 181)

Appendix D. Glossary
61200659L1-1 MX2800 STS-1 User Manual D-7
FDL
Facility datalink. FDL bits provide overhead communication between the termi-
nal equipment in ESF framing.
gateway
A device which enables information to be exchanged between two dissimilar
systems or networks.
host computer
The primary or controlling computer in a multiple computer operation.
idle code
In a T3 circuit, an idle code consists of a sequence of 1100 over the entire pay-
load bandwidth.
in-band
Signaling (dialing, diagnostics, management, configuration, etc.) over the same
channel used for data.
IP
Internet protocol. A protocol which provides for transmitting blocks of data
between hosts identified by fixed-length addresses.
LAN
Local area network. A privately owned network that offers high-speed communi-
cations channels to connect information processing equipment in a limited geo-
graphic area.
local loopback (LL)
A type of test used to verify the operation of the local terminal equipment, the
CSU, and the connection between the two. The signal from the DTE is looped
back by the CSU and is sent back to the DTE.
loopback
The technique for testing the processing circuitry of a communications device.
May be initiated locally or remotely via a telecommunications circuit. Device
being tested will echo back received test data. The results are compared with the
original data.