I'm not sure how many of these were sold, but judging by the state of the packaging on the box here I'd guess it wasn't enough to warrant full litho printing! Even the interface just has a sticker on with Camputers' stamp and 'Lynx Disk Interface' written on it. The manual is a preliminary release too.

2017 Update - new pictures and I tested everything for the first time, note to self: ignore what the main Lynx manual says to start the disk interface and instead look in the actual disk manual :) XROM loads the drive code into RAM then you have commands like EXT DIR and EXT LOAD. One of the disks I found with the pile has an application on called ZEN from Avalon Software, information on which there is none.

The interface itself is merely a host between the parallel bus of the Lynx and a WD1793 controller buried in the drive unit itself. There's some driver chips (74LS244 and 245) plus a 2764 EEPROM containing DOS, everything else is done by the drive which also has a standard 34-way socket for a connection to subsequent drives, up to 4 could be connected as long as they were jumpered correctly.

Click on the Thumbnails: