Unixware /dev/term/00 access
From: Roberto Zini <email@example.com>
Subject: Re: Problems accessing /dev/term/00 (COM1) in SCO UnixWare 7.1
Date: Tue, 30 Nov 1999 08:56:16 +0100
Ernest Evans wrote:
> I'm trying to do some basic serial port access work on my SCO Unix box and
> I'm getting no where fast.
> This system is a Pentium III 400 with 256 MB and UnixWare 7.1.
> I have an application that needs to access COM1, so I went into the scoadmin
> tool, brought up the Serial Manager and enabled COM1 as a software
> controlled serial port running at 9600 baud, 8 bits no parity, 1 stop bit,
> with data set for both incoming and outgoing.
> After I did this, SCO indicated the proper term name to use was
> So, I wanted to test and make sure everything was working properly, so I
> hooked up a Null-modem cable to the serial port on the Unix box and plugged
> the other into the serial port of a PC. On the PC I brought up
> Hyperterminal and set it up with the same settings to wait for data from the
> Unix box.
> I then went to my command line on the Unix box and echoed a string of
> characters to the device:
> # echo "test string" > /dev/term/00s
> I expected "test string" to pop up on my Hyperterminal window on the PC, no
> dice, I got nada, zip. In fact the Unix command line did not return until I
> hit Ctrl-C, and then it returned with an error:
> Unable to create device /dev/term/00s
> Now I know the device exists, and UnixWare seemed to have no problems, but
> I'm getting no where. I looked on the SCO website but none of the technical
> articles addressed the problem I'm encountering.
> Are there other things I need to do to the serial port to make it
> Note, I have already instead a serial port server on this system, and they
> all work fine (all 8 ports), but I hadn't enabled the COM1 port until
> recently. I expected the built in COM port to work as easily as a third
> party serial port server, but maybe I'm mistaken.
> Any help would be appreciated.
> Ernest Evans
> Technical Lead: Globalsoft LLC
All releases of UnixWare 7 issued so far have a bug in the serial
driver which prevents the COM ports from being used unless you cross
pins DCD and DTR on the UnixWare side of the connection; this has been
confirmed by SCO and a patch is in progress (I've tested a beta copy
of the patch and the problem seems fixed now). In the meantime,
if you want to access a UnixWare 7 system via an enabled serial port,
make sure you build a cable with DCD and DTR pins crossed (UnixWare
side) and you'll be fine.
Hope this helps !
Roberto Zini email : firstname.lastname@example.org
Technical Support Manager -- Strhold Sistemi EDP Reggio Emilia(ITALY)
"Has anybody around here seen an aircraft carrier?"
(Pete "Maverick" Mitchell - Top Gun)
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