GSM-noise "buzz" issue

Joerg Reisenweber joerg at
Sat Sep 20 17:33:23 CEST 2008

Am Fr  19. September 2008 schrieb Werner Almesberger:
> [ Cc'ing the hardware list again. I think you dropped it by accident. ]
> Angus Ainslie wrote:
> > Can someone suggest a digikey part number so the less hardware oriented
> > might try it ?
> If you don't mind the "short everything" case, then I think any 2.5mm
> audio plug will do fine. The microphone signal is at the tip/center,
> while ground is on the outmost ring.
> Regular stereo plugs (with only three rings) will short the left
> speaker to ground, but that shouldn't be a problem.
> Here's what this looks like:
> From left to right:
> - the headset suppressor, with the ground thingy folded back onto
>   itself and soldered to all other contacts
> - a standard 2.5mm stereo plug
> - the Openmoko headset's plug
> 2.5mm stereo plugs should be available at any local parts store.
> I even had no problems finding them in Argentina ;-)

I suggested this maybe a month ago on a German FR-forum, I'm still waiting for 
results but I've been promised they'll eventually come in.
Don't forget you have to set up FR to actually not switch to headset.state 
when inserting a jack. Easiest way to me seems to rename/delete original 
gsmheadset.state file and replace it by a copy of gsmhandset.state

We would appreciate very much every report on this, preferably of the result 
of inserting short-jack during a call with buzz.
Also particularly I myself would "love" to hear reports of reproduceable bad 
buzz in Germany PLZ-90xxx (Nuernberg/Fuerth/Erlangen), so I would get to know 
about a place where I actually could travel to, to test buzz myself here :-)

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