> I took another look at the web page, and, unless the manufacturer of the
> modems is named True Digital I don't think there is any mention of the
> brand of the modems.
99% of all modems built today are digital. Modems that connect to a POTS
line have an A/D converter on the front end to resample the data that is
then given to a DSP which does all the work. The way the PM3 probably
works is the digital data that comes in on the PRI would be split out and
converted to the individual channels is split up into digital data streams
and fed to the DSP's in the box. You eliminate one D/A and A/D step and
the noise that can be injected between those steps.
The actual implementation could be done in house or purchased from some
other vendor but this shouldn't matter.
Doug Ingraham
Rapid City, South Dakota, USA