From: Ashok Sharma (
Date: Fri Sep 23 1994 - 06:37:14 CDT

I hope this one gets through!

Lot of people responded to my original question:

   I am trying to setup a dialout facility on my SunOS 4.1.3_U1.
   I am having difficulty trying to get my c program to talk to
   the modem port. (/dev/ttya).
   The program just hangs while trying to open this port.??

Thank you very much for everyone who answered my question.

Here goes the summary.....
Basically, my problem was with the device file /dev/ttya.
The name of the device file usually used for modem is /dev/cua0 with
major device = 12 and minor = 128.
Also, the command ttysoftcar -n /dev/cua0 must be in the rc.local
to switch off software carrier detection.
There is a procedure in the "System and Network Admin " manual in
chapter 11.

The short version is
cd /dev
mknod cua0 c 12 (This is linked to /dev/ttya)
chmod 600 cua0
chown uucp cua0

Next, add the following in /etc/ttytab

cua0 "/usr/etc/getty std.9600" unknown off remote secure.
Another solution is to do the following:
1.) As Superuser, I made the device cub0 for dial-out.
   T then moved ttyb to ttyd0 for dial-in.
2.) I edited /etc/ttytab to include
    ttyb "/use/etc/getty std.9600" unknown off local secure
    ttyd0" /use/etc/getty std.38400" dialup on remote

3.) Using eeprom, I set

4.) I turned off soft carrier on ttyd0. In /etc/rc I set
    /usr/etc/ttysoftcar -n ttyd0 >/dev/null 2>&1

5.) I edited /etc/remote as shown in the System and Network Admin book.

6.) Re-booted the system
Finally, some good reading material can be found in the O'Reilly Book
"Managing UUCP and Usenet" by Tim O'Reilly & Grace Todino.

A PostScript file by Syed Zaeem Hosain from


TSSC NZ Telecommunication System Support Center

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