[Elecraft] K2, FD, and N1MM

[Vic Rosenthal]

I long ago built this into my K2. I used the wire intended for ALC, which I don't use, connected to the DTR pin of the DB9. 
The ALC line conveniently goes to the K2 control board through the connector with the RF board. I put the transistor on the back of the control board, along with a pair of Schottky diodes connected to the dit and dah inputs to the microprocessor.
Then all I had to do was activate the K2 menu option that allows simultaneous paddle closure to key the rig. 
No extra wires needed.

Vic 4X6GP

> On 8 Jul 2016, at 20:48, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
>> On Fri,7/8/2016 10:17 AM, Robert G Strickland wrote:
>> So, as Guy states and Don infers, using an interface device is probably preferable to a direct computer-radio setup. YMMV and OMD.
> 
> When I used a K2 for contesting, I made up a simple adapter that split out the DTR line from the computer to an NPN transistor that keyed the radio. Details begin on page 51 of this set of Power Point slides. The NPN inverter is shown on page 53. Following slides suggest how to get varying degrees of fancy.
> 
> http://k9yc.com/HamInterfacing.pdf
> 
> As has been noted, the K2 does NOT have a standard RS232 interface, and a standard DB9 cable wired for RS232 CANNOT be used directly. The K2 uses pins 2, 3, and 5 for serial interface. Other pins are used for other functions. When you build a K2 accessory that has a DB9 connector, clear instructions are provided for building a suitable cable to interface to a standard RS232 port.
> 
> One thing that was WRONG about K2 accessory kits was that Elecraft provided parallel wire cable for the interface. That cable SHOULD use twisted pairs, one pair for each signaling circuit between the K2 and the computer. Ordinary CAT5 cable is an excellent choice. This is shown on pages 53-55.
> 
> I successfully used this setup to control and key the radio both with WriteLog and N1MM.
> 
> 73, Jim K9YC
>