How Does An Isdn-Controller Work - AVM FRITZ!Card PCI Installation Manual

How Does an ISDN-Controller Work?

5.2 How Does an ISDN-Controller Work?
An ISDN-Controller serves as the connection between ISDN
and your computer. The ISDN cable supplied connects to the
S bus and thus to the local exchange of the telephone net-
0
work.
Any telecommunication service, for instance Internet, Fax G3
or telephony, is implemented using "protocols". These pro-
tocols stipulate the procedures used for data transmission
between the subscribers. They ensure smooth communica-
tion and adjust such parameters as transfer speed and data
compression during transmission. Both communications
partners must support the protocol to be implemented, for
example T.30 for G3 fax or HDLC transparent for the Internet.
The driver software for the ISDN-Controller FRITZ!Card PCI
must support the right parameters for every connection and
pass them on in real-time to both local applications and the
remote station. Transfer to the communications software
takes place in the computer via the COMMON-ISDN-API inter-
face, CAPI for short. CAPI establishes the connection be-
tween the ISDN-Controller and the installed applications like
FRITZ!. The driver software for the ISDN-Controller FRITZ!Card
PCI thus is also known as the CAPI driver.
FRITZ!Card PCI has a special CAPI driver for each operating
system supported; the applications work identically and
therefore can be used universally with CAPI 2.0. The modules
of the FRITZ! communications software are also based on
CAPI 2.0, as are a number of programs by other manufactur-
ers. AVM provides the system drivers AVM ISDN CAPI Port
Driver and ISDN NDIS WAN CAPI Driver for programs that re-
quire a modem or a network adapter.
FRITZ!Card PCI – 5 How FRITZ!Card PCI Works 37