On Mon, Nov 28, 2011 at 7:40 PM, Dwayne Reid wrote= : > At 03:33 PM 11/28/2011, Carey Fisher wrote: > >Can anyone tell me how to interface to the microphone of a Plantronics > >Headset that uses the dual, 3 circuit, WECO-type plug (it looks like two > >stereo plugs in one shell).... > >I've tried the typical > >Electret circuit (5VDC through a 2k2 resistor) but no audio. Any chance > >the mic is a dynamic mic? > > The mic is most likely an electret. Pretty much every Plantronics > headset that I've touched over the past many years has used electret mics= .. > > Question: did you try swapping the polarity of the mic connections? > > dwayne > > Yes, I tried swapping the plug around but it should work either way since the plug is symmetrical and non-polarized. I think I have an issue with the electret bias supply. The Plantronics data sheet seems to call for 5VDC thru a 265 ohm resistor whereas I'm using a 2.2k resistor that's typical for many handheld comm mics. I'll change the resistor and see what happens. > -- > --=20 Carey Fisher Chief Technical Officer New Communications Solutions, LLC 678-999-3956 careyfisher@ncsradio.com --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .