[Elecraft] K3IOB to P3 cable pinout (E980287)

[Dick Green WC1M]

Hi all,

I just bought an upgraded K3 that has a KIO3B board. It didn’t come with the E980287 cable that connects the KIO3B RJ45 jack to a P3. I have all the parts and tools to make such a cable, but want to make sure I have the pinout correct. The only info I found for that is on the schematic for the KIO3B Digital I/O Module. Here’s what I think the pinout should be:

RJ45                       9-pin RS232 female (1, 6, 8 N.C.)
1    N.C.
2    TXD               2 (RXD)
3    N.C.
4    GND              5 (GND)
5    RXD               3 (TXD)
6    N.C.
7    DTR                4 (DTR)
8    RTS                 7 (RTS)

The main thing I want to be sure about is the TXD/RXD connections – i.e., that they should be crossed over, like a null modem cable.)

Any help will be appreciated!

73, Dick WC1M