For medical use with no documentation available anywhere. Very expensive current version from a different supplier to replace this one, of German manufacture. There is a small unlabelled switch on the main unit box recessed but accessible by user and a corresponding one in the battery compartment of the r/c. Only uses 6 commands of a SAA3004P IC capable of hundreds of commands. Could the switches change 2 preset banks of codes for operating 2 such sets of kit in close proximity ?
The remote control sometimes fails to operate/alter the device but the visible red LED always pulse on command send. I've now checked that all 4 IR LEDs also always send. Before scoping pulse stream and delving deeper I suspect its a problem with one of these awkward to replace tiny switches on send end or receive end intermittently making or breaking. As only one set is used I may bypass this altogether, but anyone found such a symptom before.
-- Diverse Devices, Southampton, England electronic hints and repair briefs