Re: 2Modem phone-line communication

Hi,

Well, I have lots of information in my book (below) about modem
communications. What you want to do requires that you do two things (one
easy, and one more difficult).

First dialing and answering a modem. I have examples in my book, and you
can download DesktopSerialIO from my homepage. It is a .NET dll for serial
communications that makes the interface as simple as possible (I hope).

Second, is the creation of a command and response protocol that will send
the information between your PCs necessary to do the "screen update." I
presume that you are not trying to send entire images, etc., but are simply
sending a series of messages that may be interpreted by the receiving progam
so that it can do whatever screen update is needed?

Such protocols are ad hoc. That is, you decide what a command means (and if
a response is required), and write code that implements the sending of the
command and the interpretation on receipt. A protocol can be as simple or
as complex as you need it to be. There aren't any rules. I have example
code in my book for a command/response protocol that could be used -- but it
may be more complex than you really need. What I'm saying is that there
isn't any single "right way" to do this. There are lots of possibilities
and what actually you should implement depends on things that are not
revealed in your post -- and there is lots of "wiggle-room" after that.

Feel free to ask specific questions here, and I'll try to help.

***

--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition, ISBN 1-890422-28-2, Mabry Publishing (391 pages, includes CD-ROM).
July 2004.
See www.hardandsoftware.net for details and contact information.


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