Appendix 3: Glossary
Many of the terms in this glossary were defined with the assistance of
Newton’s Telecom Dictionary, by Harry Newton. To order a copy, call
1-800-LIBRARY or write to: Telecom Library Inc., 12 West 21 Street, New York,
New York 10010.
Busy tone
A signal generated by the central office indicating that the line you are calling
is busy.
Call Progress Tone
A tone sent from the switch to tell the caller of the progress of the call.
Examples are audible ringing, re-order, busy, timing, etc.
Central Office
Telephone company facility where subscribers’ lines are joined to switching
equipment for connecting other subscribers to each other, locally and long
distance. (Also called CO.)
Centrex
Business telephone service offered by a local telephone company from a local
central office. Centrex is leased to businesses as a substitute for a
business-owned PBX or key telephone system.
dB
A decibel is a unit of measure of signal strength.
DTMF
Dual-tone multi-frequency. Push-button telephone signaling. When you touch
a button on a pushbutton pad, it makes a tone, actually a combination of two
tones, one high-frequency and one low-frequency.
Factory default
A setting programmed by Teltone. You can change this value with one of the
programming commands. If necessary, you can use the Restore Defaults
command to return to factory defaults.
Forced disconnect
Method used by the telephone company to clear a line. When the called party
goes on-hook, the central office returns an open (that is, drops loop current) of
at least 800 ms to the calling party. This is also known as Calling Party Control
(CPC), or Cutoff on Disconnect (COD).
Polling Controller Reference Manual
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