chan_mobile on raspberry pi3, Asterisk 15.1.5

I wanted to route calls from my Asterisk 15.1.5 on my pi3 over Bluetooth from my cellphone.

Wasted a few days trying to get chan_mobile working. Followed this guide and this post. I could get the phones to dial out etc, but there was something missing - audio! 

I could not hear audio in either direction - dialing in our dialing out.

Turns out the pi3's Bluetooth controller is useless in this context, since it seems to use eSCO (Extended Synchronous Connection Oriented) link. There are no SCO packets passed during the phone call. These are the two posts that gave me the clue, although on the 3rd day.

I could not get eSCO disabled either:

root@jungle:~# modinfo bluetooth -p
disable_esco:Disable eSCO connection creation (bool)
disable_ertm:Disable enhanced retransmission mode (bool)
root@jungle:~# 

Luckily I had an old usb bluetooth adapter lying around in my spares collection:

root@jungle:~# lsusb |grep -i blue
Bus 001 Device 004: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
root@jungle:~#

I am happy to report this adapter ended up working perfectly for me.

jungle*CLI> mobile show devices
ID              Address           Group Adapter         Connected State      SMS
nexus5x         XX:YY:ZZ:AA:BB:CC 1     dlink           Yes       Free       No 
jungle*CLI>; 

You may also find this post useful when dealing with multiple BT adapters, and if one of those require a pairing challenge.

Free Tip:

Did you know, 19252590082 is a publicly available Echo Test Number?