Operation Manual

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Appendix C: Support for Multiple Subscriber Numbers
Appendix C:
Support for Multiple Subscriber Numbers
Since the adoption of DSS1 or “Euro-ISDN”, all new ISDN
lines installed in Germany are Euro-ISDN lines.
Several terminal devices may be connected to a single
ISDN line. ISDN operators typically assign several numbers
to each line: in Euro-ISDN these are called “Multiple
Subscriber Numbers” or MSNs. A specific terminal on a
Euro-ISDN line can be addressed by dialing a specific
number among those assigned to the subscriber line.
The assignment of a specific MSN to a terminal device is
programmed into the device itself.
The older technique of addressing terminals by a suffixed
digit (called the EAZ, for Endgeräteauswahlziffer ), which
was used in the German national ISDN protocol 1TR6, is
no longer valid in Euro-ISDN.
Many CAPI 1.1-based applications for DOS, Windows 3.x
or Windows 95 support EAZ addressing, but not the
assignment of an MSN.
Such applications can still be used on Euro-ISDN lines. By
configuring them to respond to the EAZ 0 (zero), they can
be made to answer incoming calls for any MSN.
Using MSN.EXE
If it is necessary to assign a CAPI 1.1 application a certain
MSN, this can be done using the DOS program MSN.EXE.
This program is available only for the DOS and Windows
3.x operating systems. For a summary of all the program’s
functions, run MSN.EXE with no command line arguments.
Mapping an MSN to an EAZ
To map an MSN to an EAZ, proceed as follows:
1. Configure your application for a certain EAZ (from 1
to 9). Refer to the application’s manual for
instructions. If the application is configured for
What are MSNs?
CAPI 1.1 applications
and MSNs