You could consider an alternative approach; whether its practical will depend on what you are trying to achieve.
VOIP normally uses the SIP protocol; your router is bascally emulating a digital phone as far as the network connection is concerned, and then does the conversion from digital to analog (to emulate the old POTs line and allow you to keep existing analog phone equipment).
In parallel with the router's SIP-based connection, you could add a second connection on the same number, with software running on a Pi. My understanding is that this should 'just work'.
Software would depend on what you wanted to do; maybe a 'softphone' such as Linphone would do. Or one of the packages where the Asterisk PBX software is teamed with a (relatively) user-friendly front end for configuration - e.g FreePbx. Or maybe (software skills permitting) you could adapt some existing software. Asterisk has an API which should allow you to detect incoming calls; last time I looked it wasn't well documented, but it can be beaten into shape.
VOIP normally uses the SIP protocol; your router is bascally emulating a digital phone as far as the network connection is concerned, and then does the conversion from digital to analog (to emulate the old POTs line and allow you to keep existing analog phone equipment).
In parallel with the router's SIP-based connection, you could add a second connection on the same number, with software running on a Pi. My understanding is that this should 'just work'.
Software would depend on what you wanted to do; maybe a 'softphone' such as Linphone would do. Or one of the packages where the Asterisk PBX software is teamed with a (relatively) user-friendly front end for configuration - e.g FreePbx. Or maybe (software skills permitting) you could adapt some existing software. Asterisk has an API which should allow you to detect incoming calls; last time I looked it wasn't well documented, but it can be beaten into shape.
Statistics: Posted by stevend — Sat Aug 02, 2025 7:27 pm