Having built the cassette interface I hooked the headphone socket of my Linux laptop to the Harlequin EAR socket, and using playtzx I 'simulated' being a cassette player. I downloaded a few Spectrum games from the World Of Spectrum, typed the obligatory LOAD "" on the Harlequins keyboard, and watched!!!!
Here are some screenshots for your viewing pleasure!
MicroGens Stainless Steel
Hewson Consultants, Quazatron
Quicksilvers Aquaplane, and Design-Designs Dark Star
As you can see, things are not quite as they should be with Dark Star and Aquaplane, two games deliberately chosen as they require exact interrupt timing. Dark Stars top border logo is too far over to the left hand side of the screen, and Aquaplanes full screen horizon is too high in the border. Interestingly, Vectrons 'full screen' post-loading, pre-game screen (above) displays correctly.
There is something clearly not quite right with the interrupts, so the excitement over, it's time to load up Ramsofts floating bus and interrupt test program, and to put the Harlequin through it's paces....