[Elecraft] K2 interface with steppIR and computer

[Joe Subich, W4TV]

John,

I am sending you the schematic for SteppIR's Y cable.  Pay attention as
pin 5 is not connected between the SteppIR and rig.  The jumper on the
SteppIR end is between 7 and 9 (not 7 and 8).

You can not parallel pin 3 (Transmit Data) on two RS-232 devices.
the device that is not sending data will load the transmit line
so that no data can be sent.  Doing a full parallel connection
requires a special diode matrix connection with external pull-up
(or pull down - can't remember without tracking down the old device)
resistors, etc.

73,

    ... Joe, W4TV


On 1/7/2012 10:08 AM, ke4d at att.net wrote:
> I built my serial cable for the K2 to talk to my SteppIR controller
from the Elecraft manual. Works just fine. It also talks to my computer
for HRD, N1MM etc. So I decided to work on having the two interfaces
work together like they did with my IC 746 Pro. However, building a Y
cable doesn't seem to be working out the way I want! Each device works
fine when I have it plugged into the Y cable by itself but when I plug
in both at the same time, One or the other will freeze up. I am simply
using pins 2, 3 and 5 from the K2 serial port wired straight through to
the female DB 9s at the device end and have 7 and 8 jumpered at the
external device end. What am I doing wrong?
>
> My KPA500 arrives on Monday so I'd like to get this resolved before my next project!
>
> John KE4D
> K2 #7231
>
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