[run >nil: <nil:] afax:c/afaxspl [-s] [-i n]
With the -S option, the spooler will run once only, checking for any faxes waiting to be spooled out. In this mode, it could be launched using cron/dcron/amicron at whatever times you wish to send faxes.
Otherwise it will run in background and check for faxes to spool at intervals of every n minutes, where n is the interval in minutes from the configuration file default, optionally overridden by the -i command-line switch. You could do this perhaps every 1/2 hour, (n = 30), or even at 1 minute intervals while testing.
The spooler checks for files of the form FAXSPOOL:*.SPL. These are human-readable. As calls progress, results are added to the end of the file. If successfully sent, the file is renamed FAXSPOOL:*.OK . If unsuccessful for more than the specified number of tries, it is renamed FAXSPOOL:*.ERR . Note that you can re-spool a .ERR file by using an editor to increase the allowed tries, then renaming it back to .SPL .