[Elecraft] Elecraft KX3 Owner's Manual now available(*preliminary*)

[Don Wilhelm]

Lance,

I would not think you could apply raw RS-232 levels (up to +/- 25 volts) 
to any input of the KX3 other than those designed to accept those levels 
- and that certainly would apply to the GPIO.  I would expect it to 
accept a maximum of 5 volts and a low level of zero volts - so you need 
the one-transistor circuit no matter which way you plug it.

73,
Don W3FPR

On 3/5/2012 2:50 PM, W7GJ, Lance wrote:
> Hello Olli,
>
> The advantage is that I could possibly pull out the RTS line from my one RS232 cable
> to the computer, and simply add it to the amplifier PTT plug in ACC2.  I would not
> have to build a transistor switch to directly trigger the PTT line, which would have
> to be broken out from the custom MIC plug.
>