KDS 8-Bit Printer Port

About

8bit printer port by KDS. Connects to the regular 34pin 7bit Printer Port Connector, and does somehow expand it to 8bit. Contrary to other 8-bit printer port expansions, as long as the KDS v2 software driver is not loaded the CPC works in 7-bit mode as though the KDS v2 interface is not there.

The exact I/O mechanism used by KDS is unknown. All that we know is that it splits the port &EFxx into fragments.

Versions

There are two versions:

The first one requires a power supply input and has a switch on top. It does not provide compatibility with CP/M.
The later one does not require a power supply input and does not have a switch. Compatibility with CP/M is provided.

The original version was first advertised in April 1985, these adverts didn't mention whether or not it requires a power supply input (normally, its data latch should need a power supply).

A year later, in April 1986 newer adverts included a note that a power input isn't required, which may refer to a new version, and which may mis-use the signal levels as supply voltages - if so, it may require some programming cautions (such like not to switch all signals to LOW level for longer periods), accordingly it may be incompatible with software from the older version.

Below are two photos, one showing a power-supply cable, one not showing one. Both have 34pin connectors, so both are probably printer-port-related hardware (although the photo with power cable is claimed to show a KDS Serial Interface with 50pin connector, which is obviously nonsense).