putty

hi guys i have some questions concerning putty

1. I have a modem of CX930xx type. When i do: at+vsl=? the result does not contain either 14 nor 15 labels. Does it imply that this modem has no option to provide headset i/o? To have one I need another modem?
2. I set vls label to one of existing options like internal or external audio and dial atd <somenumber>. When the call is answered, I have no sound. I mean i hear nothing what is said on the other side of the connection. What s I'm doing wrong?

Will be very pleased to get some guidance on this topic, for never worked with putty earlier.
By the way, tried it both from linux and windows - the same problem....
Thanks in advance.