Operation Manual

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Appendix The Applications Interface CAPI 2.0
Appendix: The Applications Interface
CAPI 2.0
Introduction
COMMON ISDN API (CAPI) is a standardized software
interface that provides applications with access to ISDN
adapters on basic-rate and primary-rate lines. Applica-
tions that build on this standard interface use uniform
mechanisms for communication over ISDN connections,
and thus do not need to adapt to the peculiarities of
particular manufacturers’ hardware. This means that
such applications are also unaffected by future exten-
sions or hardware modifications: CAPI makes such
changes transparent to the application. ISDN hardware
manufacturers benefit from this standard too, since it
makes all kinds of applications compatible with their
products.
CAPI contains an abstract definition of ISDN services
which is independent of the specifics of underlying
telecommunications networks or the adapter cards used
to connect PCs to ISDN. The specification provides an
interface that is easy for application programmers to
use, and thus offers uniform access to various ISDN
services such as data, voice and fax transmission, video
conferencing and telephony.
CAPI has evolved into an internationally recognized stan-
dard. Key in this development have been the numerous
advantages offered by this uniform interface: indepen-
dence from specific manufacturers and consequent high
investment security, a wide variety of compatible applica-
tions for all kinds of operating systems and ISDN proto-
cols, etc. ISDN (the Integrated Services Digital Network)
is becoming attractive for an increasing number of
companies since it affords fast and reliable transfer of
information in many different forms.
What is CAPI?
Benefits of CAPI