Technical information

INSTALLATION AND ADMINISTRATION GUIDE
160
One of the scheduler's Unix server processes may have stopped servicing requests. Stop and restart the fax
scheduler to resolve this problem.
vfxsched restart
Communications and modem problems
Problem
Permissions on the port keep changing.
Solution
This is due to another process attempting to use the port, and this causes failures as the two programs contend for
access to the device. VSI-FAX requires exclusive access to the serial device used to communicate with the fax
modem.
Most commonly, this is due to a getty command attempting to start a login on the port. This must be disabled
permanently. Although methods for doing this vary from machine to machine, we will detail some common
procedures here.
Note
You must be in root to complete these procedures and you usually have to edit the ownership and permissions on
the port one final time once you've disabled the gett y.
Platform Method
SCO Unix
Disable the getty on the port ttyXX by entering disable ttyXX. This permanently turns off getty
access to the port, leaving it free for VSI-FAX.
System V
Release 2
and 3
The /etc/inittab file contains a list of all programs that are run automatically, and this includes all
the getty entries. One line in this file mentions the tty that is of interest to you. This line must have its
third field changed from respawn to off. Once this file is saved, run init q to make the changes
take effect.
System V
Release 4
These machines use a ttymon process that monitors each port and automatically runs a login when
a connection is established. You must use your system administration facilities to ensure that no
activity is undertaken on your fax device port.
Note
Intel-based machines usually store their per-port getty information in two places. This means that changes
/etc/inittab are lost when the kernel is rebuilt. Look for the getty line in the file,
/etc/conf/cf.d/init.base, or in all the files in the /etc/conf/init.d/ directory. Make the change in
/etc/inittab plus the appropriate /etc/conf file, and run the init q command. A kernel rebuild is not
necessary.
A rogue process may be running on the port. Recall that VSI-FAX must have exclusive control of the port to which the
modem is connected. One way of detecting rogue processes is by the use of the ps and grep commands:
# ps -ef | grep ttyXX
Many operating systems provide a program that helps you track down processes that are using any given file, and
you can use it to find which process is using the device. The /etc/fuser (file-user) command takes a list of
filenames and searches through kernel memory and reports the process ID of any program using that file. Once the
PID is given, run ps -ef <PID> to identify what the process is.
Problem
The fax modem answers calls but terminates during negotiation.
Solution