MIc2 don´t TX in voice call

I have connected Mic2 in the differential mode without filter LC.
The voltage measure in electret mic is 1.40v.
The mic was tested with the OpenAT example of PCM Record and Play and the functionality was ok.
The parameters are for default.
I haven´t connected speaker2.
With the AT command (at+speaker), i´ve tested the 3 and 13 options.
I haven´t tx audio in call´s (Out-in)
How can i do??.
Charles

The problem has been solutioned.
I´m updated the firmware to the r74a and now i have the tx in both mic´s.