i have problem with xiaomi mi a1 and bluetooth radio of ford fiesta car.
I connected an Android phone to a vehicle via bluetooth to make/receive calls.
Connecting the device via bluetooth was simple. Making calls, however, was a challenge. The vehicle reports that the Android phone is always without cell reception, and therefore will not place calls. Furthermore, the vehicle's head unit (aka receiver) shows a "no reception" indicator for the Android device's cell reception.
Placing calls from the Android device through the vehicle's audio system works as expected. This also shows that the Android device has ample cell reception to make calls.
with the bt hci log i see that:
when phone connects bt to radio, the phone sends this info:
+CIND: 0,0,1,3,0,4,0
legend +CIND:("call",(0,1)),("callsetup",(0-3)),("service",(0,1)),("signal",(0-5)),("roam",(0,1)),("battchg",(0-5)),("callheld",(0-2))
when the signal strength on the radio disappears and reset all (zero) the phone send this info:
+CIEV: 3,0 +CIEV: 4,0
3 = service, 0 = no service (previously was 1) 4 = signal, 0 = no signal (previously was 3)
but the phone in realty upgrade the signal strength from 3 to 4!!!!!