Simulate incoming call on own android device with Handsfree

Question

I would like to create app, which would simulate in-comming call on handsfree device based on some app events. I found that there are main two ways. First approach use to create RFCOMM and communicate with HFP over AT commands. Unfortunately I spent lot of time with this approach without success. I'm able to establish RFCOMM but not able to receive any AT commands. Now, I'm thinking to use second approach. If I would be able to simulate in-comming call, it would start vibrate the handsfree automatically. Don't you know, if is possible to do that? Probably to broadcast intent, that phone receiving call?