OT - help with SCO communication problem

[Leefp1 at aol.com]

Looking for any SCO gurus to help diagnose a problem.  

In a sentence, the problem is I have lost serial communication from a Windows 
XP Terminal running Anzio Lite to a SCO host and cannot figure out why.

Environment:  SCO OS 5.0.3.  Host is Intel based SCSI box with two serial 
ports on the motherboard.  Com 1 (tty1A) is used for a dial up modem; Com 2 
(tty2a) is used for the serial connection to the Windows box.  This terminal at 
this site has worked for several YEARS with no maintenance and no problems.

Problem:  As of this past Friday morning when people at this site started 
working, the communication would not work.  Worked on Thursday; did not work on 
Friday.  Two things happened in between:  electrical storm Thursday night 
(Windows box was turned off, but dial up modem connection, used for internet 
access, on that box was left connected); some System admin work on the Unix host, 
e.g. running fsck.

The strange this is that if I disable tty2a and then reenable it; Unix sends 
a getty to the windows box and the login prompt appears.  But no keystrokes 
will be accepted. I am not at the site now, but I wish I would have tried 
sending a date prompt to the terminal to see if it would have showed up... I suspect 
it would.  Thus, in my laymen's terms, it appears the unix host is able to 
send to the windows box but the windows box cannot send back.

My first thought was that the electrical storm fried the Windows serial port 
(it had only one, com 1).  So I installed a separate board with two more ports 
(Com 4 and Com 5).  Same result... I could get a login to come up but could 
not send keystrokes from the terminal.

So...  any ideas what circumstance could cause this behavior?  By the way, 
there is a null modem in the connection between the unix box and the terminal.  
In case the problem was in the wiring between the two, I physically took the 
terminal to the room where the host is and connected directly from serial port 
to serial port with a short cable (but of course still had to use the null).  
Same result.  Could it be the null modem?  I will take a new one there Tuesday 
to find out, but I doubt that is the problem.

Also interesting, if I uncheck the "full duplex" option on the Anzio 
communication menu, I can at least get keystrokes to echo to the screen, although it 
is gibberish and will not perform a line feed.  I have no idea what that means.

Any help?  Thanks much.

-Lee
---------------------------------------------
Lee B. Walker
Walker & Company
5307 Front Royal Drive
Cross Lanes, WV 25313
304-419-0013
leefp1 at aol.com
www.walkeronline.com
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