Telos Zephyr Xstream User Manual page 358

USER'S MANUAL
Billing Telephone Number The main phone number which all calls on hunt group or a PRI are
billed to. This information may be required when configuring a PRI PBX.
Bit Error Rate The basic measure of errors on digital transmission paths. It is usually expressed
as the number of errors per number of bits. For example, the allowable bit error rate on a BRI
circuit is 1 x 10 E7 (one bit error in 107 bits or 1 error in 10 million bits).
Bit Error Rate Test See BERT
Bit Rate The capacity of a digital channel. ISDN calls are set up at a given bit rate, either 64Kbps
or 56Kbps. The bit rate of a circuit‐ switched connection cannot be changed during a call. See
Kbps.
BLEC Building Local Exchange Carrier. A LEC who covers the occupants of a single building (or a
small group of buildings) only. Often Telecom services are provided by a BLEC as a service or
incentive to potential tenants. If a BLEC offers Long Distance Service it is covered by the same
regulations as any other LEC.
Blocking When a circuit switched call cannot be completed. The percentage of blocked calls to
the number of calls attempted forms the basis of a statistic called "grade of service". While it is
economically infeasible to build a network that would have no blocking, the Telcos are held
accountable by the utility commissions to keep blocking below tariffed levels. The concept of
blocking cannot be applied to packet networks (they just lose packets, instead), only circuit
switched networks.
Blue Alarm Also called an Alarm Indicating Signal (AIS). A keep‐ alive signal sent if a problem
occurs mid‐ span in a T‐ carrier system. The blue alarm signal is required because in some cases
T‐ 1 repeaters will become unstable if inadequate 1's density is not maintained.
BOC ‐ Bell Operating Company One of the regional telephone companies that were owned by
AT&T before divestiture in 1984 (i.e. New England Telephone, Ohio Bell, etc). The 22 BOCs were
divided among the RBOCs at divestiture. See RBOC.
Both Way Trunks see combination trunks.
BRI refers to 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 where ordinary T‐ 1 trunks
(or any other digital carrier system) are used to extend ISDN BRI service. BRITE uses 3 DS0
channel per BRI ‐ One for each B channel and one for the D channel. See Repeater.
BTN See Billing Telephone Number.
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.
Called Party Address This is the destination phone number of a call delivered to a switch. For
instance this could be the CLID of a call delivered to a PBX using DID or two‐ way trunks. See also
DID.
Caller ID A CLASS feature on an analog line that provides the number of the calling line as a
burst of FSK data (modem tones) following the first ring. Also called Calling Line Identification.
See also CLASS.
Appendix 10 – Glossary 346