Writing a softmodem driver should be fairly tricky, all in.
It looks like you need to setup a thread to convert the digital data going
out to frequency-modulated sound with the aid of a DSP on the softmodem
card.
This thread needs to be run at a high priority, so an underrun condition is
not reached. Unfortunately, not all softmodems have a DSP, some don't have a
'datapump' either. I don't know what happens in this case (memmap the phone
line?? heehe).
Rockwell is one of the large supplier of softmodems (+generic). 3com and
Lucent Technologies are other large suppliers. AFAICT, the rockwell chipset
is used in the majority of softmodems I have seen. A while ago, the Rockwell
modem division changed hands (or something of some sort), so maybe they will
be a little more helpful if asked for info.
I must admit, I had a couple of softmodems in computers at home here, but I
ditched one for a real modem. If I can get some tech docs, I'd try my hand
at writing a driver. Hmmm...
Dan
__________________________
Daniel J Blueman - daniel.j.blueman@stud.umist.ac.uk
Undergraduate - BSc Computing Science
UMIST university - Manchester
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