[F A Q] Transmission of DTMF tones

23 thoughts on “[F A Q] Transmission of DTMF tones

  1. Q:

    My application operates with the transmission of DTMF tones; I can transmit tones, but I don’t receive them. 

     

    A:

    DTMF tones can be directly transmitted via the serial link (AT+VTS) but they cannot be decoded.  A DTMF decoder has to be inserted on application level, converting received audio signals in digital signals.

    The DTMF decoder feature will be availble on a future version of our new V2 modules (10.00.xx4).

    1. It is possible to expect DTMF decoding in GE865-QUAD or in GL865-DUAL?

      When engineering samples of GL865-DUAL will be available?

      1. The next firmware 10.00.xx4 will support DTMF decoding. It should be released Q1/2011.
         

        GL865 engineering samples are already available. Please check with your distributor.

          1. Yes 10.00.xx4 will be released for all V2 modules.

            Once #DTMF decoder will be enabled, an URC message will be sent on the serial port reporting the decoded tone.

             

          2. Including GE865-QUAD and GL865-DUAL?

             

            If Python is used – on MDM or MDM2 to expect DTMF URC?

          3. GE865 as well.

             

            The URC behavior can be set independently on each CMUX channel

             From  CMUX User Guide:

            •  Every CMUX instance has its own user profile storage in NVM
            •  Independent setting of unsolicited message.

             

            When using Python, URCs are piped to MDM.

          4. Thanks Cosmin!

             

            Btw, on my avatar picture you can see flying Griffon Vulture (Gyps fulvus) marked K02 that is equipped with GPS/GPRS tracker with GE865-QUAD inside. It is sending locations to FTP server. Still is in Bulgaria.

          5. Now that’s a bold intrepid Nikolay, congratulations! For how long is it working
            and how much is expected to? Do you have a front-end to track it on map?

          6. The tracker has solar panel for battery charging. Coordinates are taken and sent adaptively depending on battery level and solar panel level. The bird was released a month ago (27th October). Battery is still charged. We need at least 3 years, but this depends on bttery quality. I am using 1400mAh Li-Pol.

            This is first prototype. Now I am working on smaller device for eagles.

            For easy tracking, location data is uploaded to FTP server as Google Earth’s .kml file format. Just change file name from .txt to kml andopen it with Google Earth.

            The bird is in Balkan mountain nortern to the town of Sliven.

             

          7. Extremely interesant Nikolay, thank you for sharing! Maybe we need to put in place a "Hall Of Fame" for such designs.

          8. There are discussion for decode DTMF tone in GE8XX module with new firmware.

            Where I can find more information (AT command ) how do it work??? 

            If module decode DTMF then send only URC or can use like other at command (#JDR=6, QSS … ) it’s nice be if have any at command for read all received dtmf code from buffer, and clear this buffer. . .

             

             

          9. you post this:

             

            The next firmware 10.00.xx4 will support DTMF decoding. It should be released Q1/2011

            any specification of new future function???
             

             

  2. Today we have a new AT Commands Reference Guide r10 version which has the decoding DTMF commands described, AT#DTMF and AT#DTMFCFG.

    1. Hello everyone,

       

      About dtmf: we use them to transmit instruction to the ge865 during voice calls.

      It works ok, they are understood by the module.

       

      The issue is that it produces very unpleasant sounds in the speaker. Is there a way to solve this? I tried #TSVOL but could not find a way…

       

      Thank you,

      Philippe

       

      1. How do you use AT#TSVOL? There is a Note in command description:

         

         Note: The class DTMF Tones (<class>=16) refers only to the volume for
        locally generated DTMF tones. It doesn’t affect the level of the
        DTMF generated by the network as result of AT+VTS command

         

        Is AT+CLVL of any help?

        1. Hello Cosmin,

           

          Thank you for your quick reply.

           

          The way we use #tsvol:

          firstly I tried <at#tsvol=16,1,0> but this had no effect. So I tried <at#tsvol=255,1,0>, but no way, there is still this awful coming from the module speaker.

           

          About the note:

          The sound is the local effect of a dtmf signal send by another phone, not the result of a +VTS command;

           

          +CLVL:

          Of course +CLVL would lower this noise, but would also lower the voice…and we dont want this: we would like to have a HF discussion running, and during this conversation be able to send instructions to the module using dtmf, but without have these dtmf noises.

           

          Please tell me if you have an idea (but I would of course understand there is no solution to this…)

           

          Best regards,

          Philippe

          1. Hello Cosmin,

             

            Thank you for your quick reply.

             

            The way we use #tsvol:

            firstly I tried but this had no effect. So I tried , but no way, there is still this awful coming from the module speaker.

             

            About the note:

            The sound is the local effect of a dtmf signal send by another phone, not the result of a +VTS command;

            The DTMF tones received by the module from the network, are transmitted on the same audio channel together with the human voice, therefore even if the module is able to decode this tones, they cannot be filtered and muted, without muting completely the speaker.

             

             

            +CLVL:

            Of course +CLVL would lower this noise, but would also lower the voice…and we dont want this: we would like to have a HF discussion running, and during this conversation be able to send instructions to the module using dtmf, but without have these dtmf noises.

             

            Please tell me if you have an idea (but I would of course understand there is no solution to this…)

             

            Best regards,

            Philippe

            This is the only solution without using any external HW. You can try to use an external notch filter on EAR lines but at the moment I’m not able to suggest one.