ADTRAN TOTAL ACCESS MX2800, User Manual

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Appendix D. Glossary
61200290L1-1 MX2800 User Manual D-5
delay
The amount of time by which a signal is delayed. A round-trip transmission
delay measurement helps detect possible causes of protocol timeouts.
DLCI
datalink communications identifier. A unique number assigned to a PVC end-
point in a frame relay network. Identifies a particular PVC endpoint within a
user's access channel in a frame relay network and has local significance only to
that channel.
DS1
digital signal level one. Twenty-four DS0 channels make up one DS1 (total band-
width is 1.544 Mbps).
DS3
digital signal level three. Equivalent of 28 DS1s and 672 DS0s (total bandwidth is
44.736 Mbps).
DSU
data service unit. A device designed to transmit and receive digital data on digi-
tal transmission facilities.
DTE
data terminal equipment. The end-user terminal or computer that plugs into the
termination point (DCE) of a communications circuit. The main difference
between the DCE and the DTE is that pins two and three are reversed.
E1
Transmission rates of 2.048 Mbps are available on T1 communication lines. See
also T1.
end device
The ultimate source or destination of data flowing through a network (some-
times referred to as DTE).
end user
Subscriber who uses (rather than provides) telecommunications services.
ES
errored seconds. A second with one or more coding violations (CVs).