[Elecraft] [K3] splitting RS232 output for 2 serial ports

[iain macdonnell - N6ML]

Hi John,

I didn't want to suggest that without having tried it (and it may vary
between COM port implementations). I'm thinking that there may be some
interaction between the two COM ports if they're electrically
connected together - e.g. if you tell the rig-control port to set RTS
and DTR to "always low", that might pull down the voltage generated by
the keying port, and cause it to not work.... you could try it, I
suppose....

73,

    ~iain / N6ML


On Tue, Aug 7, 2012 at 2:54 PM, John Shadle <shadle at katzenfisch.com> wrote:
> Do you think there would be a problem in letting both signals pass
> through to both COM ports? Wouldn't COM 1 only "look" for the
> appropriate rig control signals and COM 2 only "look" for the
> appropriate CW keying signals? Or not...?
>
> Thanks, Iain!
> -john W4PAH
>
> On Tue, Aug 7, 2012 at 5:51 PM, iain macdonnell - N6ML <ar at dseven.org> wrote:
>> On Tue, Aug 7, 2012 at 2:38 PM, John Shadle <shadle at katzenfisch.com> wrote:
>>> Hi all,
>>> I'm trying to accomplish keying with my K3 using the RS232 port and a
>>> COM port on my desktop computer.
>>>
>>> I currently use the RS232 for station logging to provide frequency,
>>> mode, etc. information and for rig control (e.g., click on a spot and
>>> then the radio changes frequency/mode). Unfortunately, the program I
>>> use (AC Log by N3FJP) does not allow you to choose the same COM port
>>> for both rig control and CW keying.
>>>
>>> My question is whether or not I could use a splitter of some type (at
>>> the K3) to go to 2 separate ports (e.g., COM 1 and COM 2), then use
>>> COM 1 for rig control and COM 2 for keying. Has anyone else done this?
>>> Is this acceptable practice?
>>
>> Sure! It'd probably be safest to make the splitter yourself - the
>> "rig-control" side needs TXD, RXD and ground, and the keying side
>> needs RTS, DTR and ground.
>>
>> 73,
>>
>>     ~iain / N6ML