Appendix D. Glossary
D-6 MX2800 STS-1 User Manual 61200659L1-1
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 (sometimes
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).
ethernet
Transmission protocol for packet-switching LANs.
facilities
The equipment used by carriers to provide communication services.
far end
The distant end to that being considered. Not the end where testing is being car-
ried out.
FCC
Federal Communications Commission. The U.S. federal agency responsible for
regulating interstate and international communications by radio, TV, wire, satel-
lite, and cable.