Hi,
Voice calls suggests that you use TAPI.
There is nothing in the .NET Framework to support TAPI. While it is
possible to implement the functions that you need (and someone may have done
so), it is more practical, IMO, to use a commercially available TAPI add-on.
I suggest that you take a look at
http://www.exceletel.com/ or
http://www.tapiex.com for controls designed for this purpose. You might
spend much more money developing and debugging your own implementation, than
by using some off-the-shelf solution.
Realize that only a small percentage of standard modems support the mode
that you need.
Dick
--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition,
ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March
2006.
See
www.hardandsoftware.net for details and contact information.