Com Port Problems

[Jim Rowlee]

I am trying to open Com 2 and I get error 68, Device Unavailable. I have 2 DOS com programs and HyperTerminal that all access the port properly (ie receive data). There is a Winmodem on Com 1 and no other serial ports. Comm 2 is at the usual place (2F8, Int 3). I tried running in straight DOS mode to no avail. I have placed the offending code below. Any ideas? Thanks...

comport$="COM2:9600,N,8,1,RS,CS0,DS0,ME"
open comport$ as #2

[Clay Clear]

I do not know for a fact that this will help, but at the top of
your code, put a $COM <size-of-comm-buffer> statement. Then, in
your OPEN statement, include a "LEN = <size>" verb. This verb
tells the EXE the maximum amount of chars that can be input at
a time (maybe also for output? I do not recall). E.G.:

$COM 8192

OPEN comport$ AS #1 LEN = 8192

Note that the LEN = does not necessarily have to match the size specified
with $COM.



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[Jim Rowlee]

Thanks for the suggestion BUT no luck, I still get Error 68, Device Unavailable.

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[Jerry Mason]

Hi Jim,

Have you tried the obvious hardware troubleshooting tricks, like removing that winmodem,
and/or trying the code on a different machine?



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[Jim Rowlee]

I haven't resorted to that yet because the port works with Procomm, Qmodem and HyperTerminal...

[Jerry Mason]

There's nothing wrong with your code, Clay, so the next guess is an
incompatibility with your hardware setup. Nobody likes to crack the case
on a working machine, but reducing your machine to the bare minimum
needed to run your code, then reinstalling the hardware one bit at a time
until the problem reappears is sometimes a huge time saver. At the very least,
it will tell you what the problem isn't.



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