[Elecraft] Digital Mode Interface for the KX3 for WSJT modes

[Don Wilhelm]

Joe,

That will work, BUT neither the KXSER or KXUSB cables could be used - 
they do not contain RTS or DTR signals.

73,
Don W3FPR

On 7/13/2012 12:30 PM, Joe Subich, W4TV wrote:
>> Given that the KX3 supplied cables only have RXD and TXD signals,
>> using the serial port to generate PTT requires that either you use 2
>> serial ports (one may be the KX3 USB cable and the other can be a
>> real port or USB to Serial adapter), or provide a "Y" adapter to go
>> to your interface.
> Or simply provide a 3.5mm stereo jack on the interface for connection
> to the KX3 CAT jack.  Properly wired, TxD/RxD go to the KX3 while
> DTR and RTS get split off (in the box) to a pair (or more) of NPN
> transistors for CW and PTT.
>
> The difficulty in dealing with a computer interface for the KX3 is
> the last of a fixed level audio output and the need to share audio
> with the operator headphones/speaker.  Levels for computer decoding
> and operator comfort are not always the same <G> which means a
> buffer/splitter amplifier, external speakers with separate volume
> control and headphone jack or some other "extra box".
>
> 73,
>
>      ... Joe, W4TV
>
>
>
> On 7/13/2012 10:12 AM, Don Wilhelm wrote:
>> Bill,
>>
>> You may want to re-think using the serial port on your interface.
>>
>> Most data mode applications like to use the same COM port for rig
>> control (OK, maybe just frequency display) as they use to activate DTR
>> or RTS for PTT.
>>
>> Given that the KX3 supplied cables only have RXD and TXD signals, using
>> the serial port to generate PTT requires that either you use 2 serial
>> ports (one may be the KX3 USB cable and the other can be a real port or
>> USB to Serial adapter), or provide a "Y" adapter to go to your
>> interface.  Use of the "Y" adapter precludes the use of the KX3 USB cable.
>>
>> There is nothing wrong with generating PTT from the audio stream, or
>> just using VOX in the KX3.
>>
>> 73,
>> Don W3FPR
>> On 7/13/2012 9:51 AM, Bill Conkling wrote:
>>> I am working on an interface in a box w/pcb.  Once you use a box, you can do
>>> anything.  I plan to have full serial port and two audio cables from
>>> computer.  Transformers in the audio chain and a 10K/1k attenuator in mic
>>> input to KX3.  I will split the serial port to provide proper connections
>>> for CAT, PTT, and CW as n1mm handles the K3.
>>>
>>> Whole thing in a 2.5X2.5X1 box.
>>>
>>> Big plans....
>>>
>>> ...bill nr4c
>>>
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