SUMMARY: Modem problem after reboot

From: Stefan Hein (
Date: Thu May 12 1994 - 16:17:42 CDT

        Hello Sun-managers,

        a few days ago I posted the follwing question:
> A few weeks ago I installed a ZyXEL modem on a Sun 4/260 running
> SunOS 4.1.3 (no patches) connected to ttyb. I created /dev/cua0, made a chown uucp and
> chmod 600 for this device. I edited /etc/ttytab, /etc/gettytab and
> executed ttysoftcar -n ttyb.
> Everything was O.K. and the modem was useable for dialin and dialout.
> After a reboot (I made a system backup) dialin still works, but
> when I try to dialout I get:
> /dev/cua0: all ports busy.
> There are no left over LCK?? files, no process is using this
> port and ttysoftcar shows a "n" for ttyb, so what happened?

        It turned out to be a SunOS 4.1.3 problem! Installing patch
        100513-04 solved the tty-problem. Thanks to all responders, the
        answers are summarized below.

        Thanks again,


John Valdes wrote (thanks John):

Make sure that in /etc/ttytab, you changed the 'local' field to 'remote'
(or anything, as long as it's not 'local'). So your ttytab entry for
ttyb should look similar to:

ttyb "/usr/etc/getty std.38400" dialup on remote

What the 'remote' does is prevent the 'ttysoftcar -a' that runs from
/etc/rc on reboot from asserting the carrier detect line in s/w (ie, it
sets ttysoftcar to no for ttyb; ttysoftcar only enables s/w carrier
detect for those lines in ttytab marked local). With s/w carrier
enabled, getty will open the serial line, preventing access to it for
dialout. Make this change, 'kill -HUP 1', and then try dialing out.

Nico Garcia wrote (thanks Nico):

                   /dev/cua0: all ports busy.

           There are no left over LCK?? files, no process is using this
           port and ttysoftcar shows a "n" for ttyb, so what happened?

           Thanks for your help, I will summarize,

Hmm. Check the ownership and permissions on /dev/cua0 and /dev/ttyb,
run an fuser -k /dev/cua0 and fuser -k /dev/ttyb, and make sure no one
is dialed in on that line. Then download and install Sun patch 100513-4,
which fixes a number of tty bugs and enables RTS/CTS flow control.

Also, consider installing flexfax from This requires
no /dev/cua0 device, installs easily, and auto-configures many modems
including Zyxel. It also can provide dial-in and fax-in/fax-out, and
supports kermit or tip for dialing out.

Dave Weitzel wrote (thanks Dave):

Can you try kermit if you have it on your system like the

kermit -l /dev/cua0 -bBAUD_RATE <ENTER>

Kermit usually shows more output than tip. I would
suspect that there is still a lock file in /var/spool/locks
or /usr/spool/uucp or something. Kermit should tell you.

Michael Pavlov wrote (thanks Michael):

First of all you need Jumbo tty patch T100513-04
Then if you still getting this problem - WELCOME to the club :<

Good luck.

Nishan Sandhar wrote (thanks Nishan):

Did you change the line in /etc/ttytab to the following: -----+
ttyZ3 "/usr/etc/getty std.38400" dialup on remote

By default, it is "local". If its remote, your startup scripts should be
running the ttysoftcar command on it automatically...



************************************************* * Stefan Hein * * Technical University of Berlin * * TIB 3.1 * * Gustav-Meyer-Allee 25 * * 13355 Berlin * * Germany * * * * Phone : (+49)-30-314-72843 * * Fax : (+49)-30-314-72603 * * e-mail : * * ham : DL7AOS * *************************************************

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