Voice modem command to play a sound file

[pratheeshtu]

Hi,
I have a problem at Voice Communication.I have to play a wav file through modem.For that i am issuing the following commands in sequence.

AT+FCLASS=8
AT+VTD=10
AT+VLS=4
AT+VSM=1,8000,0,0
AT+VTX

Everything is working fine,except no voice is comming.I have tested on both SM56 PCI(Motorola)and Dlink modems.Please help me to find out a solution to this?Or send me any source to find out this problem?

regards,
Pratheesh.

 

[pansophic]

I believe that you must send the WAV file through the WAV device associated with the modem. Modems typically take a 2, 3 or 4 bit sample at 7200Hz. This is significantly different than your WAV file's configuration.

In theory, once you have set +VTX to the modem, then you would play the WAV through the WAV device, it would be converted to the modem's raw data format and shipped out through the modem.
pansophic

 

[pratheeshtu]

Hi pansophic,
Thank you for reply.
After issuing the VTX command i am getting only a garbaged sound.
I know it is actually playing,but not getting proper sound.But using 'supervoice'(3rd party software) i am getting the correct wave output.Can u please help me!

 

[pansophic]

Are you sending the WAV file directly out the modem?

I've only used WAV files in Linux, and there you send the file through PVF Tools (the equivalent of the WAV device in Windows) and the WAV file gets converted to the .rmd (raw modem data) format before being sent to the modem.

Are you using SuperVoice's SDK? I've never used it myself, but it would appear that you simply use the VOC_WaveToModemFile method to send a WAV file to the modem.

Did you get your modem from Pacific Image Communications, or are you using your own voice modem? There are some significant issues with certain modems and certain libraries. It may be that the libraries from PIC and the modem that you are using are simply incompatible, although it looks as if SuperVoice will allow you to configure many of the options that might cause incompatibilities.

You may also need to look at your modem and determine the sampling rate that is configured. Make sure that the INI file is configured correctly:

WAVESAMPLINGRATE = 7200

for a 7200Hz sampling rate. If it is set to 0, it automatically defaults to 11025Hz, which your modem may not support.

Also check:

BITSPERSAMPLE
CONVERTTOWAVE
LOCALBITSPERSAMPLE
LINEPLAYVOLUME

Good luck!
pansophic