Opening the phone line over the speakers without dialing-up.

How can I open up the phone line over the speakers without having to dial-up? Also, how can I play sounds or music into the phone line?

Thanks, August.

And the point of doing this would be what?

Communtion with people on the other end.

Certain modems are called voice / fax modems.
These can be made to appear as certain types of sound card with audio input and output channels.
One of the simple apps which came with my old modem (wow, long time ago) was able to act as a simple answering machine.

Phones and C++.
Voice modem.
Also search the forums for 'TAPI'.