I can highly recommend renting a protocol analyzer to go between your computer and the sign you're working on. Something like an HP 4951A from ElectroRent (that's who I'd call in Toronto anyway) will tell you without fail what's passing from your PC to the sign.

Alternatively, you can do something clever like wrap your serial communications module in something that logs the input and output streams in real time (or maybe Win32::SerialPort has a trace feature that can be turned on). You need to be able to see the character data as well as the control lines, RTS, CTS, DTR and DSR (if they're being used -- you might be using ON/XOFF instead).

Once you can gurantee what's going on between the PC and the sign, then you can proceed to debugging your Perl code.

Yes, I have spent some time slaving over a hot protocol analyzer doing data communications work. :)

--t. alex

"Excellent. Release the hounds." -- Monty Burns.

In reply to Re: talking to serial in w2k + latest activestate by talexb
in thread talking to serial in w2k + latest activestate by tachekent

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