TapHome supports SIP communication with doorbell systems.

doc_tap_SIPsyst;

Features   doc_tap_Feats;

• ring notification for iOS and Android devices
• 2-way audio
• video stream (M-JPEG, H.264, H.265 and other formats supported by VLC library)
• audio and low-framerate video frames automatically forwarded via TapHome Cloud
•                      doc_tap_ring_audio;

Integration with doorbell systems consists of 2 steps: 

doc_tap_2steps;

1) Preparing your doorbell for communication with TapHome Core         doc_tap_1PrepCore;

GrandStream	2N	DoorBird	Akuvox

2) Configuring TapHome SIP Doorbell          doc_tap_2ConfigDoorb;

More info

doc_tap_MoreInfo;