- B -

B4

ISO page size 10" x 14" (255 mm x 353 mm); one of the available NaturalFax page width formats.

B8ZS

Binary 8 Zero Substitution; a technique used to maintain required ones density in T1 communications. See also ones density.

B bit

See A B C D bits.

B channel

A timeslot on an E1 trunk, T1 trunk, or telephony bus that carries voice data and in-band signaling. B channel is an abbreviation of bearer channel. See also D channel, ISDN.

back end power

Power to the back end logic; back end power is applied to the back end logic through the power isolation circuitry.

bandwidth

The difference between the highest and lowest frequencies of a transmission channel; in general, when bandwidth increases, so does the quantity of information that can be sent through the circuit during a given time period.

barge-in

In NaturalRecognition, the ability to allow live voice input to abort playing a recorded message.

binding functions

In CT Access, service manager functions that provide the glue code to connect the service implementation to the CT Access infrastructure.

blind transfer

Call transfer method in which a call control function places a second call and then disconnects its port from the PBX before call placement is resolved, connecting the original call.

block

In Real Time NaturalFax, a subunit of a buffer that holds 256 bytes of data.

blocking (function call)

Stopping the executing process or thread while waiting for an internal completion event or signal.

blocking (telephone call)

Call control action taken by an application to refuse any further incoming calls. Depending on the telephony protocol, blocking calls on a line will tell the CO (Central Office) or switch not to offer any calls, or the line will reject every call that is being offered. The rejection method also varies according to the telephony protocol being used. Some protocols allow an application to designate a particular rejection method, such as playing a busy signal or a reverse-make busy signal. See also CO, reverse-make-busy.

blocking system

A switching system with limited switching capability cannot make all possible sets of connections. Under some circumstances, a connection cannot be made and the call is blocked. See also non-blocking system.

blue alarm

One of the three alarms to indicate problems with T1/E1 transmissions. The blue alarm occurs when two consecutive frames have fewer than three zeros in the data stream. A blue alarm sends ones in all bits of all timeslots. Also known as the AIS. See also AIS, red alarm, yellow alarm.

BSS

Base Station System; a GSM device charged with managing radio frequency resources and radio frequency transmissions for a group of Base Transceiver Systems (BTS). See also BTS, GSM.

BRI

Basic Rate Interface; in ISDN, a configuration that consists of two B channels and one D channel at 16 kbit/s.

broadcasting

Sending the same information to two or more parties. In a switching system, refers to a single input timeslot driving multiple output timeslots of a switch.

BTS

Base Transceiver System; a GSM device used to transmit and relay wireless frequency radio transmissions. See also BSS, GSM.

buffer

A data area that can be shared by hardware devices or program processes. It functions as a "midpoint holding place."

bus (telephony)

A physical system which permits the interchange of data. A telephony bus has three basic elements: lines for the data, bit synchronization (clocks), and frame synchronization (frame strobe). Most telephony buses also have a network reference -- an 8 kHz timekeeper. See also H.100 bus, MVIP.

bus (field)

In CT Access, bus is a field in the terminus structure that specifies the interface point of the switch block. See also switching, terminus.

bus

In the CT Access Switching service, specifies the interface point of the switch block. Devices can reside directly

on the telephony bus. Devices can also reside on a board's local bus and may require a switch block to access the telephony bus. See also Switching service.