AT&T DS1/DMi/ISDN-PRI manual Pam, Pcm

	GLOSSARY	GL-17
primary rate	A standard Integrated Services Digital Network (ISDN) frame format that
interface (PRI)	specifies the protocol used between two or more communications systems. PRI
	runs at 1.544M bps and, as used in North America, provides 23 64K-bps B-
	channels (voice or data) and one 64K-bps D-channel (signaling). The D-channel
	is the 24th channel of the interface and contains multiplexed signaling
	information for the other 23 channels.
private network	A network used exclusively for handling the telecommunications needs of a
	particular multilocation customer.
processor data	A device that provides an RS-232C data circuit-terminating equipment (DCE)
module (PDM)	interface for connecting to data terminals, applications processors (APs), and
	host computers; and provides a Digital Communications Protocol (DCP)
	interface for connection to a communications system. See also modular
	processor data module.
protocol	The first part of every Integrated Services Digital Network (ISDN) message. The
discriminator	protocol discriminator serves to identify the function — either call control or
	maintenance — for that message.
public network	A network that is commonly accessible for local or long-distance calling.
pull-in range	The range of frequencies from which the switch-clock oscillator can establish
	synchronization.
pulse-amplitude	A modulation technique in which an analog signal, such as speech, modulates a
modulation	carrier signal consisting of a series of precisely timed pulses of equal amplitude.
(PAM)	See also pulse-code modulation.
pulse-code	An extension of pulse-amplitude modulation (PAM) in which carrier-signal
modulation	pulses modulated by an analog signal, such as speech, are quantized and encoded
(PCM)	to a digital, usually binary, format. See also pulse-amplitude modulation.
Q.920 and	The level-2 (link-layer) specification for use in an Integrated Services Digital
Q.921	Network (ISDN) recommended by the CCITT for message transmission. See
	also Q recommendations.
Q.930 and	The D-channel level-3 (network-layer) specification for use in an Integrated
Q.931	Services Digital Network (ISDN) recommended by the CCITT for basic
	telecommunications call control. See also codepoint and D-channel.

Q recommendations

raw data

remote frame alarm (RFA)

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.

See unrestricted digital data.

The remote frame alarm (RFA), when received at the near end switch, indicates that the far end switch is unable to frame up on the signal sent by the near end (the end receiving this alarm). Also called the yellow alarm. See also loss of frame alignment and loss of signal.