Problem:

Writes to /dev/ttyS1 fail to produce any output. Reads work ok. No
problems are observed when same hardware is booted under Windows XP.

Testing Procedure:

I have connected another machine (remote terminal) via a null modem
cable and tried to type text into both the local terminal (running
minicom) and the remote terminal. When I type characters in the remote
terminal I see them appear in the local terminal. When I type
characters in the local terminal, I do not see them in the remote
terminal.

I have tried using minicom 2.00 and 2.1. I have also tried cat
somefile.txt > /dev/ttyS1. I have tried various combinations of
hardware and software flow control. I have tried various
communications speeds (115200, 38400).

Hardware Environment:

Linux RH8 2.4.18-14
IBM NetVista (Model Type 2289)

Any clues on what might be going wrong or how I further diagnose this
problem?

jon.

Jon Seymour <jon@zeta.org.au> wrote:
> Problem:

> Writes to /dev/ttyS1 fail to produce any output. Reads work ok. No
> problems are observed when same hardware is booted under Windows XP.

Check the permissions:
$ ls -l /dev/ttyS1

--
Michael Heiming

Remove +SIGNS and www. if you expect an answer, sorry for
inconvenience, but I get tons of SPAM

Michael Heiming <michael+USENET@www.heiming.de> wrote in message news:<va5gnb.qqk.ln@news.heiming.de>...
> Jon Seymour <jon@zeta.org.au> wrote:
> > Problem:
>
> > Writes to /dev/ttyS1 fail to produce any output. Reads work ok. No
> > problems are observed when same hardware is booted under Windows XP.
>
> Check the permissions:
> $ ls -l /dev/ttyS1


Ok, I tried this and I note that it looks like this:

crw-rw-r-- root uucp ttyS0
crw-r--r-- root root ttyS1

Thing is, I am running minicom as root, so I wouldn't have thought it
would matter too much.

Out of curiousity I connected the remote machine via ttyS0 and was
able to use it without problems.

I added some trace code to the minicom source and verified that the
write() calls to the file descriptor associated with /dev/ttyS1 were
apparently succeeding (returning a value of 1 for 1 character of
output). I suspect I am going to have to instrument the kernel in
order to understand what is going on here.

jon.

"Michael Heiming" <michael+USENET@www.heiming.de> wrote in message
news:va5gnb.qqk.ln@news.heiming.de...
> Jon Seymour <jon@zeta.org.au> wrote:
> > Problem:
>
> > Writes to /dev/ttyS1 fail to produce any output. Reads work ok. No
> > problems are observed when same hardware is booted under Windows XP.
>
> Check the permissions:
> $ ls -l /dev/ttyS1

And use Kermit, not minicom. It's incorporated into recent RedHat releases
in the "ckermit" package, and is wildly more reliable and configurable.