ASR33 Teletype interfacing

HWat you call 'rattling' sounds suspiciously like "running open" - the selector magnets in the TTY have no current applied across them, hence the machine is always 'spacing', or rather, all the internal parts are rotating, rather than waiting quietly for the next pulse. I don't see in the Daedalus site exactly how the 20 (or 60) millamps of current is going to be supplied from a regular RS232 port... Your 33 has a "local loop supply" giving current to the selector magnets when you have the function knob in LOCAL position - then, as you say, it becomes a heavy, noisy, accessorized typewriter. When you switch the knob to LINE, it is expecting to be supplied with "loop supply current" from it's communication line. This current, normally 'on', is broken by the pulses representing the data, and thus the selector magnets operate the mechanism to print each character as it comes from the line. You really oughta should get a copy of the ASR33 manuals - they're pretty common, but first you need to somehow supply loop current to your TTY... this requires the right kind of interface - especially if you hook it up to a PC to test, otherwise, you're liable to drive quite a high voltage back into the PC and kill it dead - while the ASR33 just sits there and laughs. Or 'rattles', as the case may be... Fear not! You are quite close to getting it working... and if it types, punches, and reads back tape sucessfully, then the machine sounds like it's in pretty good shape and ready to work. Cheers John