apache-labs.com

I see the 7000dle mkii OC ouputs are open collector and the KPA500 are open drain.

Do I need to add pull up resistors or can I just build a regular BCD cable HD15 to DB9 with the 4 BCD lines, PTT and gnd?

Tnx
Greg

Why go to all that trouble? Why not simply make a serial port connection from the Thetis PC to the KPA500? Enable Kenwood AI command in Thetis, pick a baud rate, and follow the instructions in the KPA500 manual to set it up for Kenwood CAT control. You only need to support pins 2, 3 and 5. You will need a null modem cable (pin 2 to pin 3, pin 3 to pin 2).

If you want to really get sophisticated, you can load the Elecraft KPA500 remote control software, make a normal (not null modem) connection to the KPA500 RS232P port, and then use a virtual serial cable to connect between Thetis and the Elecraft software.

Edited to add: it's a bit shocking that Elecraft did not put the serial port pinouts in the manual. You can find the schematics here.