[Asterisk-Users] Modem => Serial ?

[Mathew Frank]

> > Actually Dan, you are mistaken here, many serial fax/data/voice modems
> > come with answering machine programs which tell the modem to
> > send the voice data through the serial line.  Also the vgetty
> > program in linux does the same.
>
> The problem is using the AT command set, not whether or not serial
> communications can carry voice. Remember that T1 is just a really fast
> serial line.
>
> The AT command set is a remnant of low power computing. You issue a
> command to get started with voice mode. Then you set it in record mode,
> and look to see if there is incoming audio. Then you issue a command to
> send audio when you have some in your queue.

This is WRONG.   Please lookup the (AT) VTR command - simultaneous voice
transmit and receive that gives full duplex for modems that support it
(including iNTRA2/4/8 in Australia, according to the manufaturer)

I spent a long time researching this (just try googling for VTR and see how
many Video Tape Recorders you will find...) some months ago when I first
started talking about using full duplex voice modems.
All this time I thought you kept ignoring me because of financial reasons
(ie maybe you would be getting the zaptel approved for australia) not
because you thought I didn`t know what I was talking about ;-)

Check these links:
http://www.vee90.net/atcom/BCM/v92/BCMV92_Modem7.html
http://pcdesguide.org/pc99/chapt19.htm which references the the ITU-T V.253
standard - "V.253 includes small corrections to TIA-695 and adds provisions
for bi-directional, digitized voice over the serial port."  (personally
afaik full duplex voice over serial sucks however - not a problem with PCI
cards tho)
http://www.vocpsystem.com/vgetty_modems.php?mode=function - the best site
(which I just spent the last half-hour finding again...)

Cheers,
Mathew