Does any1 uses their speakerphone modem?

[nivw]

Dear helpers,
I have an Intel 56K modem and an Apache modem. Both have rear mic and speaker ins.
However I can't place a call using a standard headset.
I tried using outlook and windows phone dialer.
In each case I hear the line tune and the dialing tune, but afterwards silence.

How do you do that?
What software do ya recommend I buy?

Thank.
Niv