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13. ISDN CAPI Port Device Driver 185
Using data communications software with an emulated COM
port
If the ISDN CAPI Port Device Driver is installed with its default settings, all
virtual modems are assigned to the virtual port ISDN1. Thus any software using
the UNIMODEM interface (TAPI modems) of Windows 95/98 can work with the
virtual modems. No changes to the virtual ports are necessary. Such software
includes, for instance, Windows 95/98 Dial-Up Networking and Hyperterminal.
However, using data communications software which does not support the
UNIMODEM architecture of Windows 95/98 and requires COM ports, a COM
port must be assigned to each virtual port. (Such data communications programs
include older versions for Windows 3.x).
The assignment of COM ports to the virtual ports ISDN1 and ISDN2 is only
possible during installation of the ISDN CAPI Port Device Driver (see "Installing
the ISDN CAPI Port Device Driver"). During installation, COM ports can be
assigned on the Ports page. The settings are implemented upon completion of the
installation routine.
Note: Before assigning COM ports, check which COM ports are already being
used by other hardware components such as serial interfaces.
The COM ports assigned now can be used in Windows 3.x, 95 and 98.
The following protocols are set by default:
• ISDN B2 protocol: X.75
• PPP variants: PPP over ISDN (synchronous PPP).
To configure other protocol settings, use AT commands (see Appendix A).
Example: To set up a connection to an analog BBS using 16-bit Windows 3.x
software such as Procomm Plus 3.0 and a passive ISDN-Controller over COM 3,
the modem initialization commands must be set to AT S31=8 and S51=0 (analog
modem and asynchronous PPP) in your communications software.
The modem "ISDN SoftCompression X.75/V.42bis": Using data
compression according to V.42bis for X.75 connections
Using the virtual modem ISDN SoftCompression X.75/V.42bis connections can be
established with activated data compression. This allows data to be transmitted
at a rate up to four times higher per B channel, depending on the type of data to
be transmitted. Some basic conditions must be met, however:
• The latest CAPI 2.0 device drivers are required:
The CAPI 2.0 device drivers for your ISDN-Controller must support V.42bis.
If this is not the case, the virtual modem ISDN SoftCompression X75/V42bis
is not available for selection in the installation window.
ISDNmst.fm Page 185 Wednesday, January 15, 2003 9:22 AM