On Sun, 30 Nov 1997, Hans B Pufal wrote: I'll guess you mean an ASR33 - the KSR is the keyboard send/recieve and doesn't have the punch or reader. The basic ASR simply sends the tape at 10cps under the control of the manual switch on the reader. Turning this switch on energises a solenoid at the back which releases the transmit clutch. This serialises the bits that trigger a solenoid in the reader to step the tape on by one character According to the Model33 partsbook there's an option that adds a couple of rails in the function box ('stunt box'for people brought up on Creeds :-)) These respond to XON and XOFF and close/open a pair of contacts that are wired into the reader run circuit (you'd need a diagram to see how, since you get auto and manual control IIRC). That gives you a remote reader control in the obvious way. A number of computer manufacturers - I have notes from DEC and Intel - modified ASR33's for their computers. This mod generally consisted of fitting a reed relay in series with the reader trip solenoid and controlling it from the computer's serial I/O interface circuit in some way. Most of these mods were very similar, and were used to single-step the reader when loading a tape. I've also got a Data Dynamics tty which is an ASR33's mechanics in a new case with a Data Dynamics electronic module. This gives RS232 and current loop serial interfaces _and_ single-stepping of the reader both from a button on the panel and remotely. Hope that helps. I can probably find diagrams of the above if you need them. -tony

At 22.08 30/11/97 +0000, you wrote: Hi, Hans The teletypes are syncronous machines and the speed must be exactly adjusted in order to correctly send characters. Regards, ---------------------------------------------------------------------------- --------- Riccardo Romagnoli Classic Computers, Teletypes and Phonecards collector Forli' - Italy chemif(a)mbox.queen.it ---------------------------------------------------------------------------- ---------