How Does Work Fritz!Card; Fritz!Card On The Isdn Line - AVM FRITZ!Card USB Installation Instructions Manual

How Does Work FRITZ!Card

4 How Does Work FRITZ!Card
This chapter provides basic information about FRITZ!Card on
the ISDN line and the way an ISDN-Controller functions.

4.1 FRITZ!Card on the ISDN Line

When your ISDN access is configured, the ISDN provider
installs a network terminator (NT) first. An NT is equipped
with two ISDN sockets, each of which is an external S
0
interface.
In most cases an ISDN PBX with analog extensions is
connected to one ISDN socket of the NT and a digital
terminal to the other: in this case, the ISDN-Controller.
Analog terminal devices such as telephones, answering
machines and G3 fax machines are connected to the PBX
extensions. The connected devices are addressed through
distinct telephone numbers. These telephone numbers are
referred to in the terminology of ISDN as Multiple Subscriber
Numbers (MSNs). Each ISDN line is equipped with several
MSNs.
If a PBX is connected to one of the ISDN sockets and your
computer with FRITZ!Card to the other, additional ISDN
sockets are required to connect any other ISDN terminal
devices like an ISDN telephone (see the gray area in the
figure below).
FRITZ!Card – 4 How Does Work FRITZ!Card 27