AT&T1 audio test: how to?

Hi, just another question.
I have to test the modem (WMOD2): I would like connect a phone headset (I have the DB15-DB9-4 pin plug cable).
To make a voice loopback test I should hear my voice in the headset speaker.

I’m not sure how to make this.

I’ve found these instructions on the web:
ats0 = 1
at+speaker = 1
at+cicb = 0
at+vgr = 0
at+vgt = 0


at&t1 (to start test)

I hear a “noise” in the speaker (have you ever heard a low frequency square wave on a speaker?) that ends with the command at&t2.
I try to speak to the microphone, but I don’t hear nothing of my voice.
What’s wrong?
Modem not working or (more probably) wrong command sequence?