User's Manual

Trailblazer Installation and User Manual version 1.03 50
6.8 Glossary
ANSI
Acronym for American National Standards Institute. Devises and proposes recommendations for international
communications standards.
asynchronous
A method of data transmission which allows characters, that are preceded by a start bit and are followed by a stop
bit, to be sent at irregular intervals.
bandwidth
A range within a band of frequencies or an amount of data that can be transmitted in a preset amount of time. The
bandwidth determines the rate at which information can be sent.
bridge
A connectivity advice that operates at the OSI Data Link Layer and filters and forwards packets by physical
addresses. See also router.
CD
Acronym for Carrier Detect. It is a signal generated by a modem or DSU/CSU and indicates the
presence of a carrier signal on a communications link.
CSU
Acronym for Channel Service Unit. A device used to connect a digital phone line from the phone company to a
multiplexer, channel bank, or directly to another device producing a digital signal. A CSU performs line-
conditioning and equalization functions, responds to loop-back commands sent from the central office, regenerates
digital signals and monitors them for problems, and provides a way of testing a digital circuit.
CLASS features
Acronym for Custom Local Area Signaling Services. Consists of number-translation services, such as call-
forwarding and caller identification.
clock
Is an oscillator-generated signal that provides a timing reference and generates periodic signals for the timing of
certain functions in a transmission link.
CPE
Acronym for Customer Premise Equipment. It includes all telecommunications terminal equipment located on the
customer premises, including telephone sets, PBXs, data terminals, and customer-owned coin-operated
telephones.
CTS
Acronym for Clear To Send. A signal on the DTE interface indicating that the DCE is clear to send data.
dB
Is an abbreviation for decibel, a logarithmic unit used to measure sound level or signal strength.
DCE
Acronym for Data Communications Equipment. A device that provides all the functions required for connection to
telephone company lines and for converting signals between telephone lines and DTE. Also see DTE.
DSR
Acronym for Data Set Ready. It is a signal on the EIA-232 interface that indicates a connection and readiness to
start handshaking control signals for communication to begin.
DSU
Acronym for Data Service Unit. A hardware component needed to transmit digital data over a hardware channel. It
converts signals from bridges, routers, and multiplexers into the bipolar digital signals used on the telephone
company digital lines and ensures that voltage levels are correct.
DSU loop back
Is a Telco initiated test which loops the DSU back to the Telco and is used to test the DDS circuit as well as the
DSU/CSU.
DTE
Acronym for Data Terminal Equipment. It is the end-user terminal or computer that plugs into the termination point
(DCE) of a communications circuit.
gateway
Is a device which enables information to be exchanged between two dissimilar systems or networks.