The intercom moved into the smartphone — and it’s not magic, it’s SIP/VoIP
In PDP Mobile, we turned a phone into a digital intercom: the incoming call goes through SIP to Asterisk, audio and video run over WebRTC, and the call looks like a regular one.
In PDP Mobile, we turned a phone into a full-fledged digital intercom. When someone rings the building entrance, the app places a VoIP call over SIP to Asterisk, and we use WebRTC for audio and video. To make it feel native, we integrated CallKeep — the incoming call looks like a regular phone call, without the feeling that “this is some kind of hack.”
As always, the fun part is not “accepting the call,” but real life: poor connectivity, the app running in the background, Wi‑Fi suddenly switching to LTE. We handle all of that so the call doesn’t fall apart at the worst possible moment.
We also added HLS streaming from cameras: the resident sees who is at the door first, and only then responds. Handy when it’s a courier, a neighbor, or someone who looks a little too suspiciously confident 😅
Against the backdrop of the trend toward “smart” homes and super-app UX, things like this are no longer a feature, but the baseline.