AT&T 7300 series, 7500 series, 7100 series, 2500 series, 7200 series, 7400 series manual Ncte, Nau

GLOSSARY GL-17

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MPDM	See modular processor data module.
MTDM	See modular trunk data module.
mu-255	A type of code by which analog signals are encoded to digital signals.
multiplexer	A device used to combine a number of individual channels into a common
	bit stream for transmission.
multiplexing	A process whereby a transmission facility is divided into two or more
	channels, either by splitting the frequency band into a number of narrower
	bands or by dividing the transmission channel into successive time slots.
	See also time-division multiplexing.
nailed-up connection	Obsolete. See dedicated switched connection and permanent switched
	connection.
NCTE	See network channel-terminating equipment.
network	A series of points, nodes, or stations connected by communications
	channels.
network-access unit	A circuit card that plugs into a PC’s expansion slot to connect that PC with
(NAU)	others to form a StarLAN network. See also StarLAN.
network channel-	Equipment used at a customer’s premises to provide facility terminations
terminating equipment	and signaling compatibility. Also called channel service unit and
(NCTE)	customer service unit. See also data service unit.
node	A switching or control point for a network. Nodes are either tandem —
	they receive signals and pass them on — or terminal — they originate or
	terminate a transmission path.
nonfacility-associated	A method that allows multiple PRI links to share a single D-channel on
signaling (NFAS)	one of the spans. One T1 link is therefore configured as 23 B-channels
	plus 1 D-channel, while the other spans that share the D-channel are
	configured with 24 B-channels each. See also facility-associated
	signaling and primary rate interface.
off premises	Telephones or data terminals that are not located within the same building
	or campus as a communications system or have loop lengths greater than
	3500 feet.
off-hook	A condition in which the handset of a telephone is off the switchhook or
	the telephone is activated by other means, such as through a speakerphone
	button.