Problems with Everex<->T2500 CTS handshaking

[Cerafin E Castillo]

I have seen this behaviour in relation to UART failures at above 9600 bps.
I would suggest that you lower your port speed to 9600 bps and test again.
I would also suspect the device drivers in your ISC UNIX.  Call ISC and
ask about this situation with the O/S, then call Everex and ask them about
their RTS/CTS flow control implementation.  I would also test using a
PC or UNIX system hooked-up with a null modem cable.  Run UUCP or Kermit
over this connection starting at 9600 bps and going up to 19.2 kbps to
see if a similar failure doesn't occur.  An RS-232 Protocol analyzer would
help with this kind of testing.  I suspect that the failure will be your
Everex multiport board and its drivers.  Oh, I forgot the obvious, if there
are any motherboard COMM ports (ie COMM1 / COMM2) attach the modem to
those ports and try your UUCP transfer as you are doing so now, on your
multiport board.  You might just see better RTS/CTS handling at 9600 and
19200 bps on COMM1/COMM2.  If not, then I would suspect the O/S and its
drivers.

Good Luck!

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Cerafin E. Castillo                       ||      //\\  ||\\  ||
Network Consultant                        ||     //__\\ || \\ ||  Los Altos
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