Landline as backup

Hi everyone, our internet has been pretty unstable lately, and sometimes would drop out for a few hours.
We have a landline. Is there anyway freepbx can make use of this as a secondary trunk? how?

note: my freepbx box is a VM.

Thank you.

some sort of voip ATA

sipura 2000 ata. They are old…but rock solid.

Synway makes a 4x FXS/FXO combo card that you can plug in and use for this. I set up most of my systems with a pair of incoming and outgoing lines. The extra $100 makes sense for things like outgoing alarm notification lines and for incoming wall panels. If you go this route, you will need to downgrade the DAHDI distribution to match the hardware (they are usually a version behind).

  1. Some sort of ATA device (a few mentioned here). Probably need something external since you have a VM.

  2. An outgoing trunk setup to that ATA device for placing calls. Note that caller id will match the landline and not the other numbers.

  3. Once you get inbound calls working from the ATA, add a forward (possibly a forward on disconnect) from your SIP lines to the landline number.