Re: 2Modem phone-line communication

Hi,

>>
As you suspected, I plan on sending messages between the two computers that
are interpreted on each side of the connection. The simulation program (the
real one) will only be sending updates and receiving user commands (or
key-strokes, depending on how well this kind of connection performs). The
screen updates itself completely every half-second, so large bandwidth isn't
necessary. The screen updates will most likely consist of either a String or
Byte array, depending on efficiency. As for the user commands, they will be
either simple Integers or KeyCodes. Nothing very complicated at all.
<<

By your description, you need 1920 bytes to represent a screen. With
protocol overhead, slightly less than 2000 bytes. Since a conventional
dialup modem can pass data end-to-end at a maximum speed of 33K bps (higher
speeds are restricted to connections to the internet, not between two PCs --
the speed on the telephone line is this maximum, even though the serial port
speed is much higher), your basis screen update will consume ALL of the
available bandwidth if you attempt two per second. I suspect, at the end of
the day, that you may not see much more than two every three seconds at
best, and perhaps only one per second.

Still, I see nothing very difficult about the situation, if you can live
with the bandwidth limitation. The keystrokes and other commands will not
have any significant impact on screen updates.

Building a protocol to handle this doesn't sound difficult. If I were to do
it, it might take a couple of days, though. So, don't underestimate your
time.

***

--
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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