If you have the caller id service from your phone provider and your
modem has caller id capability (accepts AT+VCID=2 or AT#CID=2 commands),
This port can cause the modem to answer the call giving the caller an
earful.

I built scud to hopefully remove my phone number from telemarketers'
phone lists. Don't know if it will work or not, but at least I smile
each time I hear my phone only ring once.

Create a file: /usr/local/etc/scud.conf to hold command line options
you want used each time it is started.