A RS232 interface by KDS Electronics
A RS232 interface by KDS Electronics.
All of them were wired incorrectly. d7 was d0, d6 was d1, and so on. Consequently you had to reverse the bit order before you could do anything useful with it.
In addition, the hardware handshaking didn't work properly, and since the ports were different to those used by the Amstrad/Pace interface, you were limited to the built-in KDS software. Which sucked.