Modify OpenMoko GSM voice

David daviD davidsalsa at
Thu Aug 2 00:39:41 CEST 2007

I am trying to determine if the OpenMoko GSM voice can be modified by software.
I have heard "it is possible" and "it is impossible". One of these is true.
Does anyone know any details about how it is possible?

The CODEC details are here:

Looking at the OpenMoko audio path, it seems that there is no way to
modify GSM voice.

 *  audio path Mic -> GSM
         o MIC2/MIC2N
         o Mic2 Volume
         o ALC Micer Mic2
         o Left PGA
         o Mic Sidetone Mux [Left PGA]
         o Mono Sidetone Volume
         o Mono Mixer Sidetone Playback Switch
         o Mono Volume
         o Mono 2 Mux [Inverted Mono 1]

   * audio path GSM -> Speaker
         o RXP/RXN
         o Rx Mixer [RXP - RXN]
         o Line Left Mux [Rx Mix]/Line Right Mux [Rx Mix]
         o Left Mixer Bypass Playback Switch/Right Mixer Bypass Playback Switch
         o Headphone Volume

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