Telos TWOx12 - Page 201

TELOS TWOX12 USER’S MANUAL
GLOSSARY OF TELEPHONE TERMINOLOGY
APPENDIX 4 189
BRI
- ISDN Basic Rate Interface- The common form of ISDN with 2 “Bearer”
Channels and one “D” channel. All three channels are on a single copper pair and
encoded with type 2B1Q coding.
BRITE
- Basic Rate Interface Transmission Extension. A technology were ordinary T-1
trunks (or any other digital carrier system) are used to extend ISDN BRI service. See
Repeater.
Business Office
- The part of the phone company where you call if they mess up your
bill, to report problems, and to order service. Not necessarily technically literate.
Central Office
- See CO
Channel
- An actual path you can talk or send data over. This is what you are paying
the phone company for. For instance, ISDN BRI lines can be ordered with 1 or 2 active
channels and these channels can be configured for voice calls (CSV), data calls (CSD)
or both (alternate CSD CSV). A channel does not necessarily have it’s own unique
telephone number. See ISDN.
Choke Exchange
- A telephone exchange which is assigned to Radio and TV stations,
Promoters, and other users which will be receiving large numbers of simultaneous
calls. The idea is to group all of these users on a single exchange so when all routes
into that exchange are in use “normal” users (on other exchanges) will not experience
blocking of incoming or outgoing calls. Trunks from other local exchanges into the
choke exchange are deliberately limited to just a few paths so callers will get an "all
trunks busy" instead of completely blocking their local exchange. However, when one
of the choke exchange users experiences a large number of calls (as when your station
runs a contest) the other choke exchange users will be blocked because all trunks into
the choke exchange will be busy. See blocking and concentration.
Circuit
- A physical path through which electrical signals can pass. It consists of a
network of conductors and other components, separated by insulators. Technically this
term cannot be applied to fiber optic or other “non-metallic” paths.
Circuit Switched Data
- See CSD
Circuit Switching
- A system where a dedicated channel is allocated to the users of that
call for the duration of that call. That channel is allocated for the duration of the call
regardless if information is being transmitted at any given moment. Bandwidth through
the channel is fixed, at no time may this bandwidth be exceeded. If this bandwidth is
not used it is wasted. While inherently inefficient, the dependable and reliable nature of
circuit switching makes it ideally suited to real-time voice and audio/video
conferencing applications. This is in stark contrast to systems where statistical
multiplexing is used. See statistical multiplexing.
CLEC
- Competitive Local Exchange Carrier. Your local telephone service provider
who is one of the new-generation providers rather than a RBOC or Independent. A
CLEC is really just an independent, albeit one formed after the divestiture of AT&T.
See LEC.
CO
- The Telco facility to which your local telephone circuit lead. Contains “Switches”
and “Trunks” as well as the local telephone circuits.
Codec
- COder/DECoder. A device which takes digitized audio and “codes” it in order
to reduce the transmission bit rate and which can also simultaneously “decode” such