
ISDN glossary
94
kap13.fm5
Profiset 70isdn, GB: A30853-X300-B501-3-7619
20.5.99
ISDN glossary
The ISDN glossary should help you understand the many
new terms and abbreviations relating to ISDN.
a/b port
Port between the TAE socket and analog terminals.
a/b converter
These devices are used to connect analog terminals, such as tele-
phone, telefax, answering machine or modem, to the digital ISDN tel-
ecommunications network. The a/b converter (a/b adapter) thereby
converts the analog signals into digital signals and controls the D
channel protocol.
APL
Public network termination point. The APL is the actual connection
point to the telecommunications network. The internal telecommuni-
cations connector (TAE socket) is attached to the APL.
B channel
The basic channel with a maximum transmission speed of 64 kBit/s.
Basic rate access
This is the ISDN basic rate access. It is the entry-level connection type
in ISDN and offers two B channels with 64 kBit/s and a control channel
with 16 kBit/s.
BZT
Abbreviation for "
B
undesamt für
Z
ulassung in der
T
elekommunika-
tion" (Federal German Bureau of Certification for Telecommunica-
tions). Terminals which have been tested and approved for connection
to the German Telekom network are assigned a BTZ number.
Call forwarding
Forward calls to another station.
Call waiting
If the line is busy, a connection request is signalled (acoustically or op-
tically) by a call waiting signal.
CAPI
Abbreviation for
C
ommon ISDN
A
pplication
P
rogrammable
I
nterface.
CAPI is a standardised interface between the communication inter-
face and the protocol interface. Any ISDN application programs can
communicate with any ISDN adapter cards via the CAPI.
CCITT
Abbreviation for
C
omité
C
onsultatif
I
nternational
T
élégraphique et
T
éléphonique which is an international consulting body for telegraphy.
The CCITT has changed over to the ITU. It publishes recommenda-
tions which are frequently viewed as standard in the international tel-
ecommunications industry.
CLIP
Abbreviation for
C
alling
L
ine
I
dentification
P
resentation and means
that the calling party’s number appears on the called party’s display.
COLP
Abbreviation for
C
onnected
L
ine
I
dentification
P
resentation
and
means the called party’s number appears on the calling party’s dis-
play.
D channel
Control channel, also known as the data channel, which is provided in
the ISDN basic rate access with 16 kBit/s and in the primary rate ac-
cess with 64 kBit/s. It is required in particular for connection setup and
cleardown.
Dial pulsing (DP)
The old signalling method in the analog telephone network, whereby
the signalling information is transmitted by interruptions on the line.
Increasingly replaced by dual-tone multifrequency signalling (DTMF).