To cut to the end, does anyone have the software disk for the Subject: line? An explanation... About 20 years ago, there was a Fischertechnik robotics kit. This contains the usual blocks, gears, etc, 2 small motors, 3 lamps, an electromagnet, 8 switches and 2 pots. And no other electonic parts. There were various interfaces sold for this, at the time they were very expensive and not suitable for the machines I had. So I did the obvious thing and boilt my own... But I have now bought the one for the BBC Micro (Part numbrer 30 564) (it turned up on E-bay with a reasonable B-I-N). It arrived exactly as described (brand new, still in the shrinkwrap). In the box was the interface module, the user manual, and a supplement to that. No software disk, although the manual makes reference to one. Fortunately, the most important program, the low-level driver that talks to the interface via the Beeb's user port is listed in the manual, so it is possible to use the thing. But I'd still like to have the demo programs for the models described in the robotics kit manual. As regards the interface itself, I've not seriously looked at it yet. It's mostly 4000-series CMOS, with a 4014 shift register for the switch inputs, a 4094 shift register driving motor control ICs for the outputs, and a 556 timer for the pot inputs (the driver program seems to use one of the timers in the VIA that controls the user port). Looks very hackable. -tony