MC55i calling test

dear friends,
I am trying to test calling function in my GSm module MC55i.but cannot hear anything on speaker.
for testing purpose i've connected my speaker directly between speaker out(pin 49) and module ground(pin 42).
what is the possible problem?

thanks in advance.

There are two DAC out interfaces EPP1 and EPP0, its better you go through manual and AT command interface document to know what command exactly activates a specific interface.