[Elecraft] [KX3] RS232 xcvr control when serial ports are occupied

[Stephen Rector]

Hi Dick:

Thanks - the diagram makes things very clear. I initially didn't think of accomplishing the split at the KXPA 3.5mm connector, but it makes sense.

Thanks,  73,

Steve NU7B


> On Jul 8, 2018, at 1:38 PM, dick at elecraft.com wrote:
> 
> Typically "sniffers" don't have the TX side connected.  RS-232 can't have
> multiple transmitters on either wire.
> 
> This is done with SteppIR controller, for similar reasons.  SteppIR
> describes a splitter cable for DE-9 connectors. The same principle (with a
> much simpler cable, just tip and ring) applies to the 3.5mm connector to the
> KXPA100.
> 
> http://www.steppir.com/wp-content/uploads/2011/10/Y-Cable.pdf
> 
> 73 de Dick, K6KR
> 
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
> Behalf Of Stephen Rector via Elecraft
> Sent: Sunday, July 8, 2018 12:31
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied
> 
> Hy home station is a KX3 + KPXA100, and I can control the radio via the
> RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to
> the station, and its controller plugs in to the KXPA serial port to sniff
> for frequency information, allowing re-tuning on the fly. This leaves no
> RS232 port left for remote control of the radio.
> 
> How do I modify this arrangement to add an extra serial port for KX3
> control? My first thought is that, since the antenna controller just sniffs
> for data, I could add a DB-9 Y-cable to provide the extra port at the
> controller serial port location. However, packets could still collide
> ...does the protocol handle this? Is there some sort of multiplexer
> available?
> 
> Thanks,
> 
> Steve
> 
> NU7B
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