modems, at commands and sound - TechRepublic
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March 5, 2004 at 11:55 AM
esmakilic

modems, at commands and sound

by esmakilic . Updated 22 years, 4 months ago

Hi,
For my final project at school I am trying to send a sound file from computer to telephone, via modem. Whenever I send it as a byte stream, it is not heard from telephone instead only a buzz is heard. Before sending the sound file I send the following commands to modem:

send(“AT#CLS=8”);
expect(“OK”);
send(“ATS39.6=1”);
expect(“OK”);
send(“AT#VLS=6”);
expect(“VCON”);
send(“AT#VTX”); //transmit
expect(“CONNECT”);
expect(“”); expect(“VCON”);

Then I send the sound file but I can not hear it from telephone. (I used a sound file with ?RAW? extension and also a WAV file which has properties as ?PCM, 8000Hz, 16 bit, mono? but none of them works) When I send the command ?AT#VSM=?? to my modem it gives me ?128, GSM/AZT,8000 129,G.721 ADPCM/AZT, 8000 and 130, IMAADPCM/AZT,8000? Does it mean I have to send a sound file with GSM format?
If someone can give me some information about transmiting sound to telephone via modem, this will really be helpful. Thanks in advance for any help.
Esma KILIC

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