[Elecraft] Kx3: How to interface UP, DOWN and PTT signal ?

[Brian Lodahl OZ2BRN]

Hi,

For the 4-pin mic pinout for the MH-3 microphone, it is listed that the 
PTT line also carries logic for UP and DOWN keys.

As I want to interface using a Heil Traveller headset, which has the UP 
and DOWN key signals on a seperate line (8-pin round standard), how are 
the logics defined for this pin (first ring on the 4-pin jack) on the 
Kx3 and MH-3, respectively ?

Would it be possible to ask for a schematic ?

73'
Brian OZ2BRN