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

[Lance Collister, W7GJ]

Hi John,

As Don explained, you can use the ubiquitous 2N2222 transistor circuit to either 
ground your PTT line from the RTS line of the serial port or KEY your transmitter 
from the DTR line of theRS232.   He also mentioned the optoisolator and that little 
50 cent chip is very convenient ;-)  I explained how you can use that on my web page:

http://www.bigskyspaces.com/w7gj/KX3.htm

GL and VY 73, Lance


On 8/7/2012 10:27 PM, John Shadle wrote:
> Thanks, Don. Are you talking about the "PTT IN" and "KEY OUT" RCA jacks?
>
> I Googled "one transistor keying circuit" and it came back with some
> amplifier keying circuits. Is that what I should be looking for, or
> something else? I'm sure the answer is obvious, but I'm just having a
> hard time seeing it. ;-)
>
> Take care.
> -john W4PAH
>
> On Tue, Aug 7, 2012 at 6:20 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>> John,
>>
>> I would suggest that you use the "one transistor keying circuit" (Google and
>> you will find many sources) for the keying and PTT. Connect the output of
>> the one transistor keyer to the K3 rear panel keying input and PTT input.
>>
>> You will still have the problem that the computer will activate those
>> signals when the computer boots, so boot the computer and than turn on the
>> K3 - or take other common sense precautions like switching the K3 to a dummy
>> load during computer boot times.
>>
>> 73,
>> Don W3FPR
>>
>>
>> On 8/7/2012 5:38 PM, John Shadle 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?
>>>
>>> Thanks!
>>> -john W4PAH
>>> Madison, WI
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-- 
Lance Collister, W7GJ
(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ)
P.O. Box 73
Frenchtown, MT   59834-0073
USA
TEL: (406) 626-5728
QTH: DN27ub
URL: http://www.bigskyspaces.com/w7gj
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Skype: lanceW7GJ
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