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Issue 5 - 04/01 A2-7
Glossary and Acronyms
Number (MSN)
-Multipoint lines, which allows terminal selection
based on CPN (Called Party Number).
µ-law
A companding technique used for PCM systems in
North America, Japan and some other regions in Asia.
N
Near-end block
The number of errors detected in transmitted data
errors (NEBE)
blocks at the originating end.
Network
A piece of equipment that terminates an ISDN
termination (NT)
connection at the customer premises. The NT1
terminates the physical interface from the central
office at the customer premises. The NT2 is an
intelligent device at the customer premises that
can provide functions such as switching and
concentration. The NT1 and NT2 are sometimes
physically combined and called the NT. NT1
provides the T reference point (T interface), and
NT2 provides the S reference point (S interface).
O
Off hook
A line state which informs the exchange (Central
Office) that a subscriber requires a service.
On hook
The unused state of a telephone circuit.
OSI 7-layer
A model defined by the ISO, in which ISDN
Model
functions are separated into 7 clearly defined
layers.
Overlap dialling
A type of dialling where the digits are sent one at a
time, each in its own separate call control message.
App02.P65 01/05/01, 09:20 7