I just bought an actiontec 56k/v.92 external serial modem to use with my Debian system. I thought it would be pretty straight forward to use.. just plug it in and go. Unfortunately that's not the case.. I can't seem to get it to be recognized.

The end goal is to use hylafax with it so I went to the hylafax page and got this command to test with (as root):

cu -l /dev/ttyS0

That results in this error:

cu: open (/dev/ttyS0): Permission denied
cu: /dev/ttyS0: Line in use

I also tried changing that ttyS0 to ttyS1 and S2 and S3 with similar results. Anybody have a suggestion on how to proceed?

Is there something holding that device?
eg. what does say?

The first thing to do is to make sure the serial port is functional. There are a couple ways to do that.

The most fundamental is to check the BIOS settings and make sure the thing is switched on. While you're there it might be wise to check on the IRQ and I/O port as they will indicate which tty you should look at when you get back into the OS. It will be on IRQ 3 or 4 normally, if it's on IRQ 3 you'll be looking for /dev/ttyS1 or /dev/ttyS3, if it's on IRQ 4 look for /dev/ttyS0 or /dev/ttyS2. The I/O port numbers specify which, but I don't recall the correlation at the moment.

In any case, when you are back to linux, get logged in as root. Once you're there it should be pretty easy to figure out which tty to use: just do 'cat /dev/ttyS0' or whichever tty you think is appropriate. If the serial port is not on that tty, you'll get an I/O error. If it is on that port, IIRC, you get nothing at all, which in this case is a good thing. Just ctrl-C to get back to the shell.

Once you have got this far, cu should definitely work.

If you have already got this far before posting, I'm not sure what to tell you except that your cu binary could potentially be broken, or your serial port could be. You might try using minicom, just make a soft link /dev/modem to whichever is the appropriate /dev/ttyS?

Good luck

Stephen

As root, try to change owner-group of /dev/ttyS0 (and the rest) like this:

chown uucp.uucp /dev/ttyS*

This should be useful.

lsof | grep ttyS didn't return any results, but I typed lsof | grep ttyS* and got the following:

bash 537 root 0u CHR 4,1 307888 /dev/tty1
bash 537 root 1u CHR 4,1 307888 /dev/tty1
bash 537 root 2u CHR 4,1 307888 /dev/tty1
bash 537 root 255u CHR 4,1 307888 /dev/tty1
getty 538 root cwd DIR 8,3 20480 307076 /dev
getty 538 root rtd DIR 8,3 4096 2 /
getty 538 root txt REG 8,3 14584 387994 /sbin/getty
getty 538 root mem REG 8,3 90152 193946 /lib/ld-2.3.2.so
getty 538 root mem REG 8,3 1243888 193966 /lib/libc-2.3.2.so
getty 538 root 0u CHR 4,2 307891 /dev/tty2
getty 538 root 1u CHR 4,2 307891 /dev/tty2
getty 538 root 2u CHR 4,2 307891 /dev/tty2
getty 539 root cwd DIR 8,3 20480 307076 /dev
getty 539 root rtd DIR 8,3 4096 2 /
getty 539 root txt REG 8,3 14584 387994 /sbin/getty
getty 539 root mem REG 8,3 90152 193946 /lib/ld-2.3.2.so
getty 539 root mem REG 8,3 1243888 193966 /lib/libc-2.3.2.so
getty 539 root 0u CHR 4,3 307894 /dev/tty3
getty 539 root 1u CHR 4,3 307894 /dev/tty3
getty 539 root 2u CHR 4,3 307894 /dev/tty3
getty 540 root cwd DIR 8,3 20480 307076 /dev
getty 540 root rtd DIR 8,3 4096 2 /
getty 540 root txt REG 8,3 14584 387994 /sbin/getty
getty 540 root mem REG 8,3 90152 193946 /lib/ld-2.3.2.so
getty 540 root mem REG 8,3 1243888 193966 /lib/libc-2.3.2.so
getty 540 root 0u CHR 4,4 307897 /dev/tty4
getty 540 root 1u CHR 4,4 307897 /dev/tty4
getty 540 root 2u CHR 4,4 307897 /dev/tty4
getty 541 root cwd DIR 8,3 20480 307076 /dev
getty 541 root rtd DIR 8,3 4096 2 /
getty 541 root txt REG 8,3 14584 387994 /sbin/getty
getty 541 root mem REG 8,3 90152 193946 /lib/ld-2.3.2.so
getty 541 root mem REG 8,3 1243888 193966 /lib/libc-2.3.2.so
getty 541 root 0u CHR 4,5 307900 /dev/tty5
getty 541 root 1u CHR 4,5 307900 /dev/tty5
getty 541 root 2u CHR 4,5 307900 /dev/tty5
getty 542 root cwd DIR 8,3 20480 307076 /dev
getty 542 root rtd DIR 8,3 4096 2 /
getty 542 root txt REG 8,3 14584 387994 /sbin/getty
getty 542 root mem REG 8,3 90152 193946 /lib/ld-2.3.2.so
getty 542 root mem REG 8,3 1243888 193966 /lib/libc-2.3.2.so
getty 542 root 0u CHR 4,6 307903 /dev/tty6
getty 542 root 1u CHR 4,6 307903 /dev/tty6
getty 542 root 2u CHR 4,6 307903 /dev/tty6
apt-get 698 root 0u CHR 4,1 307888 /dev/tty1
apt-get 698 root 1u CHR 4,1 307888 /dev/tty1
apt-get 698 root 2u CHR 4,1 307888 /dev/tty1
ftp 700 root 2u CHR 4,1 307888 /dev/tty1

Will try the other suggestions shortly..

Ok, I tried the chown suggestion and that worked! Now when I type cu -l /dev/ttyS0 it tells me I am connected. I was also able to query the modem to find it supports 0, 1, 2. Thanks for the help!