Use a raspberry PI 3 as a PBX
1) PBX system (FreePBX?) with SIP for google voice (& callcentric)
2) 1-3 extension to go to a rj11 jack (preferably 3 if possible)
3) 1 extension to send a low voltage (<5v) signal from the PI, only after entering code (for example when selecting extension 9, it should prompt for a password/code, & if the code is verified it should send a signal from a port) signal will go to door entry system & this will unlock the door
4) A few extensions that will forward the call (for John Doe press 2, & call will get transferred to cell/office)/ or to get transferred to voicemail
5) Access to listen to voicemail
6) (To be able to add message before the PBX extension list readout) (for example in urgent scenarios to be able to add message, so callers will know the info & won’t need to dial an extension)
Greetings, I am an experienced VOIP and Asterisk consultant. i have created raspberry and Asterisk based home automation systems in the past. Apart from that I have developed many IVR systems as well as call centre systems using nodejs Ari client in the in the past 2 years for various clients. please discuss in detail over chat. my recent Asterisk projects were an outdialer for a Spanish client, a call centre system for govt. of India project and an IVR for Electronic Customer Verification system.