AT&T DEFINITY 2500 series Network Manual page 332

GL-20
GLOSSARY
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protocol converter (PC)
public network
pulse-amplitude
modulation (PAM)
pulse-code modulation
(PCM)
PVC
Q recommendations
Q.920 and Q.921
Q.930 and Q.931
remote access trunk
restricted [channels]
RNX
robbed-bit signaling
A device consisting of hardware, software, or a combination of both, that
allows two systems, each using a different protocol, to communicate and
exchange messages with each other.
A network that is commonly accessible for local or long-distance calling.
A modulation technique in which an analog signal, such as speech,
modulates a carrier signal consisting of a series of precisely timed pulses
of equal amplitude. See also pulse-code modulation.
An extension of pulse-amplitude modulation (PAM) in which carrier-
signal pulses modulated by an analog signal, such as speech, are quantized
and encoded to a digital, usually binary, format. See also pulse-
amplitude modulation.
See permanent virtual circuit.
Recommendations of the CCITT that affect an Integrated Services Digital
Network (ISDN). The Q.700 series defines signaling system number 7,
which is used for common-channel signaling across networks. Q.920 and
Q.931 define a digital-access signaling system for signaling between the
customer's equipment and the network. See also CCITT, Q.920 and
Q.921, and signaling system number 7.
The level-2 (data-link layer) specification for use in an Integrated Services
Digital Network (ISDN) recommended by the CCITT for message
transmission. See also Q recommendations.
The D-channel level-3 (network layer) specification for use in an
Integrated Services Digital Network (ISDN) recommended by the CCITT
for basic telecommunications call control. See also codepoint and D-
channel.
A telecommunications channel used by an authorized user to gain access
to the communications system.
Restricted channels are channels over which no all-zero bytes can be
transmitted. The line equipment transmitters on restricted channels use
ZCS line coding.
The location code for a private-network communications system, where R
equals any digit 2 through 9 except the assigned call-detail recording
(CDR) account code prefix, N equals any digit 2 through 9, and X equals
any digit 0 through 9.
Digital signal level-1 (DS1) signaling in which up to eight kbps from each
of the 24 64-kbps channels are used for signaling in every sixth frame.
The least-significant bit of each 8-bit sample is replaced by a signaling bit.
Also called DS1 robbed-bit signaling.