AVM FRITZ!Card PCMCIA, Руководство по установке

Страница: 34 / 46

How Does FRITZ!Card Work
34 FRITZ!Card – 5 How Does FRITZ!Card Work
5 How Does FRITZ!Card Work
This chapter provides basic information about FRITZ!Card on
the ISDN line and the way an ISDN-Controller functions.
5.1 FRITZ!Card on the ISDN Line
When your ISDN access is configured, the ISDN provider in-
stalls a network terminator (NT) first. An NT is equipped with
two ISDN jacks. Each of these sockets is an external S
0
inter-
face.
In most cases an ISDN PBX with analog extensions is con-
nected to one ISDN jack of the NT and a digital terminal de-
vice 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 tele-
phone 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 sock-
ets are required to connect any other ISDN terminal devices
like an ISDN telephone (see the gray area in the figure below).