[Elecraft] Yamaha CM500 Headset is a WINNER (and a BARGAIN)

[Jim Brown]

On Wed, 23 Dec 2009 16:56:44 -0800, K6LE wrote:

>It's a stereo plug 

No, it's not a "stereo" plug, it's a 3-circuit plug the CAN be used 
for stereo, or can be used for other things like an electret mic. It 
could also be used to carry shielded balanced audio wiring. 

With this mic, the tip is audio high, the sleeve is audio return and 
cable shield, and the ring is +Vdc to power the tiny impedance 
converter inside the mic. For more on this, see 

http://audiosystemsgroup.com/HamInterfacing.pdf  

and the Appendix on audio for ham radio in 

http://audiosystemsgroup.com/RFI-Ham.pdf

73,

Jim K9YC