ISDN glossary
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glossar.fm5
27.11.98 Profiset 30isdn engl.: A30853-X300-B107-1-7619
Dual tone multi-
frequency (DTMF) A signalling method whereby the information is transmitted to the
switching centre in the form of tones with various frequencies.
Euro ISDN Uniform European ISDN standard introduced at the end of 1993.
Hold The ”Call hold“feature. The non-communicating state of the user put on
hold in the course of a consultation or toggle action.
Hunt group A number of terminals can be accessed under one call number or are
switched together to one connection. A number of basic rate accesses
can also be switched together to one connection.
ISDN Abbreviation for Integrated Services Digital Network. Service-integrat-
ing digital telecommuications network which integrates telecommuni-
cations services such as telephone, telefax,, data and image transmis-
sion in a network.
ISDN service The ISDN network offers several additional services to make communi-
cation more convenient, e.g. call forwarding, three-party conference.
These additional features are called ISDN services.
LTU Abbreviation for “ISDN line trunk unit“ .Connecting box for digital
terminals on the S0 bus.
MSN Abbreviation for Multiple Subscriber Numbers; a multiple subscriber
number of the ISDN basic rate access in a multi-device connection.
Multi-device
connection A connection whereby a number of terminals can be operated simulta-
neously on an S0 bus in point to multipoint operation.
Multiple Subscriber
Number (MSN) Assigned by Deutsche Telekom for an ISDN basic rate access with multi-
device connection. Multiple subscriber numbers are used for direct in-
ward dialling to the terminal but, unlike the direct inward dialling number,
are completely independent of each other.
NTBA Abbreviation for Network Termination for Basic Access. Network
termination of an ISDN basic rate access which is installed by or can
be obtained from Deutsche Telekom.
Park (TP) ISDN service. Abbreviation for Terminal Portability and means that a call
can be parked in order to unplug the telephone from one socket and
plug it into another socket of the same S0 bus.
Point-to-multipoint
operation Is an ISDN multi-device connection whereby a number of ISDN termi-
nals can be operated on an S0 bus.
Point-to-point
operation An example of point to point operation is the primary rate access. In this
case, only one terminal can be operated on the connection. For this rea-
son, it is called a system connection. In most cases, the system con-
nected is an ISDN PBX.
Primary rate access ISDN connection equipped with 30 B channels each offering 64 kBit/s.
Primary rate access (system connection) is only available in connection
with a standard rate or premium rate access.
S0 bus A line used from the network termination in the multi-device connec-
tion. Up to 12 connecting boxes and up to 8 ISDN terminals can be con-
nected to an S0 bus; of these, however, only 4 ISDN terminals can be
connected simultaneously without separate power supply.