Reply To: HFP Codec Negotiation Failure

[IOT747 Team]

Hello Guido,

This is strange as enabling this should just mean the AT commands are displayed via UART, but shouldn’t be changing behaviour otherwise. We tried with an iPhone SE and we could not replicat ethe issue. See below the UART log.

1) With enable_at_notifications=ON, does the module still respond to +BCS

internally on the HFP link, or is the host expected to take over the

full codec negotiation?

>> If it displays ATH for the AT command it shows this is has been handled by the AT parser and the appropriate response has been sent, eg:

ATH 13 12

+BCS: 2

If it just showed: AT ,

Then it has not been handled, and might require a response depending on the AT command.

With enable_at_notifications=ON, it should just be for display purposes, it is not meant to affect behaviour.

2) Is there a recommended way to receive +CIND / +CSQ / +CIEV indicator

updates from the AG without breaking automatic HFP codec negotiation?

>> You can set enable_at_notifications=ON, or send AT commands directly using the command: AT . 

3) Is there a non-Apple-specific way to query phone signal strength and

battery level via the IDC777 (AudioAgent commands or AT pass-through)

while keeping HFP audio fully functional?

>> You can use the command: AT

to send AT commands to the connected AG.

Eg.

AT 13 AT+CIND?

OK

ATH 13 25

+CIND: 0,0,1,1,0,5,0

ATH 13 7

OK

AT 13 AT+CIND=?

OK

ATH 13 133

+CIND: (“call”,(0,1)),(“callsetup”,(0-3)),(“service”,(0-1)),(“signal”,(0-5)),(“roam”,(0,1)),(“battchg”,(0-5)),(“callheld”,(0-2))

ATH 13 7

OK

AT 13 10

ERROR

4) We would also be interested if there is a way to toggle

enable_at_notifications at runtime without going through WRITE + RESET

>> You can actually change between these at run time, and the AT information should be enabled/disabled accordingly :

set HFP_CONFIG=ON ON OFF ON 5 ON OFF ON OFF

set HFP_CONFIG=ON OFF OFF ON 5 ON OFF ON OFF

Details of iPhone test with AT notifications enabled.

call 13 outgoing 121
OK
ATH 13 7
OK
ATH 13 15
+CIEV: 3,2
ATH 13 11
+BCS:2
ATH 13 7
OK
SCO_OPEN
ATH 13 15
+CIEV: 3,3
CALL_ACTIVE HFP 13
ATH 13 15
+CIEV: 2,1
ATH 13 15
+CIEV: 3,0
call 13 end
OK
SCO_CLOSE
ATH 13 7
OK
CALL_IDLE HFP 13
ATH 13 15
+CIEV: 2,0