I have noticed on Q268X and SL6087 the following problem:
Before voice call using ATD; the current drawn indicates that the module is in
“ACTIVE mode with telecom stack in Idle Mode”
During voice call setup attempt it is in
“GSM Connected Mode (Voice)”
So far, so good.
If the receiver of the call cancels before answering, I get BUSY indication (as I should), but module then stays in
“ACTIVE Mode”
It does not go back to
“ACTIVE mode with telecom stack in Idle Mode”.
If instead of cancelling the call, the receiver answers and then hangs up normally, the module does go back to “ACTIVE mode with telecom stack in Idle Mode”.
Tested and confirmed on firmwares R7.2a, R7.44, R7.45 and R7.46 using Q268X and SL6087 on development kits.
UART1 disabled with UART2 used for the AT-commands.
All modes above have been deduced through looking at actual power consumption values, and mapping those to what is shown in documentation.
No OpenAT program is running on the modules. All settings are at default except for UART1 being disabled.