Anybody who started with this thread (and many thanks to Mike Ford), I got a second hand wall-wart power supply which puts out 9v dc 500 mA. The connector on the wall-wart cable has a socket for a central pin and an outer conductive barrel. The socket is +, the outer barrel is - according to the power supply label. I plugged it into the Etherprint-T Plus and it ran fine for at least 5 minutes (after which I unplugged it and went to bed). I'll let you know if it causes trouble later. YMMV, of course, but as far as I can tell Mike's forwarded post took care of me perfectly. Thanks, Mike! - Mark