I know someone who needs to connect a modern USB printer into a some kind of industrial machinery that uses a DB15 (15 pin, D-Sub I take it?) on the factory floor. It would be nice if I could find a ...

You can't daisy-chain parallel-port printers. If you've managed to get things plugged in, it's probably because you've stuck one printer cable into the serial port of the other printer. You'll need ...