# Decoding DTMF **URL:** \ **Category:** Legacy AirPrime modules\ **Created:** [February 16, 2009, 3:03pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938 "2009-02-16T15:03:54Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![marven](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@marven](https://forum.sierrawireless.com/u/marven)\ **Post date:** [February 16, 2009, 3:03pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/1 "2009-02-16T15:03:54Z")
Hello, I need to decode DTMF signals to control my robot but how can I do this with GSM module? Do you know which GSM module support this feature? and how? Thanks alot ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [February 16, 2009, 3:35pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/2 "2009-02-16T15:35:43Z")
Why do you need to use DTMF? It’s not a terribly effective way to use a GSM link… ---
**Author:** ![marven](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@marven](https://forum.sierrawireless.com/u/marven)\ **Post date:** [February 16, 2009, 6:22pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/3 "2009-02-16T18:22:26Z")
I want to use cellphone numbers 1-9 to control my robot. That is the reason. ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [February 16, 2009, 6:47pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/4 "2009-02-16T18:47:08Z")
Isn’t that going to work out rather expensive…? ---
**Author:** ![marven](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@marven](https://forum.sierrawireless.com/u/marven)\ **Post date:** [February 16, 2009, 7:06pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/5 "2009-02-16T19:06:46Z")
yes but I need this to control my system whereever I want. Not like RF, wi-fi or bluetooth. ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [February 16, 2009, 7:15pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/6 "2009-02-16T19:15:14Z")
> [@marven](#): > > Not like RF “RF” just stands for “Radio Frequency” - GSM is, of course, an RF connection… (as are WiFi and Bluetooth)… ---
**Author:** ![marven](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@marven](https://forum.sierrawireless.com/u/marven)\ **Post date:** [February 16, 2009, 7:19pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/7 "2009-02-16T19:19:02Z")
For RF I mean RF com. modules. Thanks for RF explication. Can you help me for DTMF or not? I dont want to discuss details. thanks. ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [February 16, 2009, 8:09pm UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/8 "2009-02-16T20:09:15Z")
Note that, when you press the buttons on a cell phone, the phone itself doesn’t actually generate DTMF; instead, it sends signalling messages to the GSM network, and the GSM network generates the tones as they leave its digital network. The GSM speech codecs are optimised for speech, and don’t carry DTMF too well - but Wavecom do claim to be able to do this with the DSP features in some modules. Download the latest SDK, and look in the ADL User Guide under “Audio Services”… ---
**Author:** ![marven](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@marven](https://forum.sierrawireless.com/u/marven)\ **Post date:** [February 17, 2009, 6:21am UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/9 "2009-02-17T06:21:14Z")
Thanks. Yes I heard that the wavecom modules have this feature. I couldnt find the SDK, where can I download? ---
**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\ **Post date:** [February 17, 2009, 7:25am UTC](https://forum.sierrawireless.com/t/decoding-dtmf/2938/10 "2009-02-17T07:25:51Z")
[viewtopic.php?f=3&t=3155&p=11729&hilit=SDKs#p11729](http://www.wavecom.com/modules/movie/scenes/forums/viewtopic.php?f=3&t=3155&p=11729&hilit=SDKs#p11729)