[Elecraft] A Finger PTT switch for use with my Yamaha CM-500 headset?

[Jeff Hall]

I've found that using VOX outdoors is problematic due to background noise, so I'd like to wire up a finger PTT switch that works with my K3 and Yamaha CM-500 headset.  I have an existing finger PTT switch that was designed for use with a Yaesu FT-11R HT.   There are 3 stereo plugs wired to the finger PTT switch apparatus:

 - MIC IN (3.5mm male stereo plug)
 - MIC OUT (2.5mm male stereo plug)
 - EAR IN (3.5mm stereo plug) (this normally plugs directly into the HT's EAR OUT jack)

When this is all hooked up to the HT, pressing the finger switch puts the radio into transmit mode, just as if you pressed the TX button on the HT directly.

I'm wondering if I can use this switch, along with some adapters to get things working with my K3 and Yamaha CM-500's boom mic:

1. Couple the CM-500's MIC OUT plug to the switch's MIC IN plug using a 3.5mm female to 3.5mm female stereo adapter coupler
2. Connect the switch's MIC OUT to the K3's rear MIC IN (or my Microkeyer II's ext. MIC IN) using a 2.5mm female to 3.5mm male adapter
3. Plug the Yamaha CM-500's EAR IN plug into the K3's phone jack

I don't have anything to plug into the K3's PTT IN jack and I'm not sure this is even needed.  Maybe all I need to do is continue to use the K3 in VOX mode, but now the MIC will only activate when I close the switch AND talk into the microphone?

Thought I'd ask before running out and buying those adapters...

73 de Jeff, W6UX