🚀 go-pugleaf

For some reason my news reader doesn't like some of the responses in 
this thread, so please excuse if this is slightly off target of the 
question or the info is redundant.

DSVD modems support multiplexing voice and data over a single 
connection. For this to be functional, both ends of the connection 
must have DSVD capable modems (which are compatible of course). 
There is a recently established standard which is now being adopted 
by most modem manufacturers. Compatibility should not be a problem 
once everyone is signed up to the standard.

How they work: If you have two modems connected in data mode at 
28.8K, DSVD modems make it possible to "shave off" a small portion 
of the total data through-put and allocate it to passing digitized 
voice. Generally, this voice channel will be 8K or less. This is 
sufficient to produce "international call" quality. If I understand 
correctly, the source for the voice channel must be either a 
telephone or microphone connected directly to the modem.

I have heard that in the very near future the SDK for a popular desk 
top windowed operating system will have built-in support for 
controlling DSVD modems.

Based on what I understand of the discussion, it will not be 
possible to use the voice capbilities of DSVD modems over the 
Internet because your service provider's system is attempting to 
process all the data sent to it. It the modem on their system does 
not filter out the digitized voice, the result would look like 
garbage data to the other system.

The Internet Phone works by encapulating digitized voice data from 
your sound card inside TCP/IP compatible packets. These are routed 
like any other packet to the destination where the TCP/IP wrapper is 
removed. The data is then fed as an input to the sound card at the 
other end.

Hope this helps.
Rich.