Now with the usual discussion which arises with compatible internal modems for FULL DUPLEX voice etc... It really makes me think (again) about serial communications.... Most external modems will now talk at 115k2 so maybe some will explain when/what/how/etc of why a serial interface could NOT be developed ?? Gary .
Hi, Serial voice modems use separate jacks for audio in and audio out. The audio stream cannot be passed through the serial line. BR, Dan ----- Original Message ----- From: "Gary" <gary@ausmail.com> To: <asterisk-users@lists.digium.com> Sent: Wednesday, June 04, 2003 7:17 AM Subject: [Asterisk-Users] Modem => Serial ?> Now with the usual discussion which arises with compatible internal > modems for FULL DUPLEX voice etc... > > It really makes me think (again) about serial communications.... > > Most external modems will now talk at 115k2 so maybe some will explain > when/what/how/etc of why a serial interface could NOT be developed ?? > > Gary > . > > > > _______________________________________________ > Asterisk-Users mailing list > Asterisk-Users@lists.digium.com > http://lists.digium.com/mailman/listinfo/asterisk-users > >
On Wed, Jun 04, 2003 at 09:05:54AM +0300, Dan wrote:> Hi, > > Serial voice modems use separate jacks for audio in and audio out. > The audio stream cannot be passed through the serial line.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. cheers, Woody> > BR, > Dan > > ----- Original Message ----- > From: "Gary" <gary@ausmail.com> > To: <asterisk-users@lists.digium.com> > Sent: Wednesday, June 04, 2003 7:17 AM > Subject: [Asterisk-Users] Modem => Serial ? > > > > Now with the usual discussion which arises with compatible internal > > modems for FULL DUPLEX voice etc... > > > > It really makes me think (again) about serial communications.... > > > > Most external modems will now talk at 115k2 so maybe some will explain > > when/what/how/etc of why a serial interface could NOT be developed ?? > > > > Gary > > . > > > > > > > > _______________________________________________ > > Asterisk-Users mailing list > > Asterisk-Users@lists.digium.com > > http://lists.digium.com/mailman/listinfo/asterisk-users > > > > > > _______________________________________________ > Asterisk-Users mailing list > Asterisk-Users@lists.digium.com > http://lists.digium.com/mailman/listinfo/asterisk-users-- Woody
On Wed, 2003-06-04 at 01:49, Anthony Wood wrote:> On Wed, Jun 04, 2003 at 09:05:54AM +0300, Dan wrote: > > Hi, > > > > Serial voice modems use separate jacks for audio in and audio out. > > The audio stream cannot be passed through the serial line. > > 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.> > > > ----- Original Message ----- > > From: "Gary" <gary@ausmail.com> > > To: <asterisk-users@lists.digium.com> > > Sent: Wednesday, June 04, 2003 7:17 AM > > Subject: [Asterisk-Users] Modem => Serial ? > > > > > > > Now with the usual discussion which arises with compatible internal > > > modems for FULL DUPLEX voice etc... > > > > > > It really makes me think (again) about serial communications.... > > > > > > Most external modems will now talk at 115k2 so maybe some will explain > > > when/what/how/etc of why a serial interface could NOT be developed ?? > > > > > > Gary > > > . > > > > > > > > > > > > _______________________________________________ > > > Asterisk-Users mailing list > > > Asterisk-Users@lists.digium.com > > > http://lists.digium.com/mailman/listinfo/asterisk-users > > > > > > > > > > _______________________________________________ > > Asterisk-Users mailing list > > Asterisk-Users@lists.digium.com > > http://lists.digium.com/mailman/listinfo/asterisk-users-- Steven Critchfield <critch@basesys.com>
With a software modem, you cannot bypass AT commands and directly acces the hardware for voice applications, as you have the source code for the modem driver himself? BR, Dan> 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.
> > 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