AVM FRITZ!CARD Classic, Manual

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2 All about FRITZ!Card
12
addressed by way of multiple subscriber numbers (MSN). Each
ISDN connection has at least three MSNs. If you have connected
your PBX to one of the ISDN sockets and your PC containing
FRITZ!Card to the other ISDN socket, you will require additional
ISDN sockets to connect other ISDN terminal equipment such
as an ISDN telephone (see gray area in the following Figure).
Fig. 2 Typical Configuration of an ISDN Multiple Connection
However, there are also PBXs which offer digital as well as ana-
log extensions. You can connect ISDN terminal devices to these
digital extensions. Digital extensions are also known as inter-
nal S
0
interfaces. They are an alternative connection facility to
external S
0
interfaces.
Whether you connect your FRITZ!Card to an internal or external S
0
interface - the ISDN terminal device is not the FRITZ!Card but the
ISDN software on your PC, such as the FRITZ! modules FRITZ!data,
FRITZ!fax and FRITZ!vox for example.
All incoming calls from the ISDN are distinguished not only by
their multiple subscriber number but also by their service indi-
cator. No such differentiation takes place for calls coming in from
the analog network: here telephone calls and faxes share the
Analog-Telefon mit
Anrufbeantworter
ISDN-Telefon
Fax
Schnurloses
Telefon
ISDN-Anlage
mit ananlogen
Nebenstellen
S S
O O
NT NT
S S
O
O
S S
O
O
Rechner mit
FRITZ!Card