[Elecraft] K2 RS-232 Interface

[Don Wilhelm]

Phil,

For the K2, the PTT function can be done using the K2 CAT command set if 
your PC application implements it.  Normally applications implement PTT 
and keying through the DTR and RTS signal lines on the RS-232 
interface.  Since the K2 implementation of the AUX I/O connector uses 
the pins that would normally connect to the DTR and RTS signals for 
internal K2 signaling lines, those pins must not be connected to a 
serial port signal, and detection of DTR and/or RTS active must be done 
externally to the K2.  That is usually accomplished using a simple 
transistor, diode and resistor circuit like that mentioned in the 
Digipan (and other PSK31 applications) documentation.  An optoisolater 
is also commonly used to develop PTT or keying closures if there is a 
need to isolate the computer ground from the K2 ground.

Note for K3 users - the K3 does allow attachment of a standard serial 
cable to its RS-232 connector and will detect DTR or RTS active for PTT 
or keying whichever is selected in the K3 menu (make certain your 
solftware application and the K3 agree about which line is for which 
purpose).

73,
Don W3FPR.

Phil Kane wrote:
> On 5/3/2010 9:50 AM, Jim Brown wrote:
>
>   
>> Nearly all radios and ham logging software use only pins 2, 3,
>> and signal return for radio control and information. The K2 uses
>> the other pins on its DB9 connector for other functions that are
>> VERY different from the RS232 standard.
>>     
>
>   I'm using MixW as my data and logging program with my K2/100
>   and the KIO2 "special cable" for several years now.  Up to now
>   I haven't been using the CAT function for frequency tracking,
>   but I do want to start.  The COM port works fine for PTT rig
>   control.
>
>   Pardon me if I ask a "newbie" question, but what settings in
>   the K2 menu do I have to check/change to implement this.  If
>   it's documented somewhere please point me to it.
>
>   With thanks.
>
> --  73 de K2ASP - Phil Kane
>     Elecraft K2/100   s/n 5402
>
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