callattendant

A python-based automated call attendant, call blocker, and voice messaging system running on a Raspberry Pi. Screens callers and block robocalls and scams with a low-cost Raspberry Pi and modem. Maintained by emxsys on GitHub, where it has earned 125 stars from the community.

It's actively developed around python, uml, telephony, and is a solid reference for anyone building with these tools.