Many years ago, a company I used to work for did a Centronics port for TURBOchannel. The timing we wound up using was data stable 500nS before strobe, strobe lasts 1mS, data remains stable until 500nS after strobe. IIRC, this is fairly close to what we found in Centronics documentation, but I don't remember what documents we found or what the exact numbers in that document were. -- Roger Ivie rivie(a)teraglobal.com Not speaking for TeraGlobal Communications Corporation

Yeah, well, ACK and BUSY are pretty much at the whim of the designer, as well. I really don't remember all the fun we had trying to come up with a state machine to give us an interrupt when the printer had accepted the last byte we gave it and was ready to accept another. I seem to recall things like some printers hold ACK normally deasserted then pulse it asserted to signal they've accepted the byte while others do it the other way around. And you can't count on the relationship between BUSY and ACK pulses, either, although IIRC PCs tend to ignore one of them (I don't recall which one). For such a simple interface, Centronics sure is a mess... -- Roger Ivie rivie(a)teraglobal.com Not speaking for TeraGlobal Communications Corporation

Why did Synertek refer to the SYM-1 as the SY-VIM-1 in some areas? Whatever became of Synertek? Jeff -- Collector of Classic Microcomputers and Video Game Systems: Home of the TRS-80 Model 2000 FAQ File http://www.geocities.com/siliconvalley/lakes/6757

Then only those SYM-1's produed early in the run in '78 would carry the VIM-1 label? Jeff -- Collector of Classic Microcomputers and Video Game Systems: Home of the TRS-80 Model 2000 FAQ File http://www.geocities.com/siliconvalley/lakes/6757

If you connect an Atari 825 printer to a PC, the printer fries itself. This is an OEM Centronics 733 printer. Why does it make smoke? I've burned three printers and know my signals/cables are correct. I've run tons of printers off ataris that weren't atari printers. Why does this printer call the fire dept when connected to the PC?? P.S. I've one more that works perfectly so I can experiment.................................. I will produce the pinouts for each machine, but wanted instant gratification..... Regards all, Jeff -- ----------------------------------------------------------- Jeffrey S. Worley President Complete Computer Services, Inc. 30 Greenwood Rd. Asheville, NC 28803 828-277-5959 Visit our website at HTTP://www.Real-Techs.com THETechnoid(a)home.com -----------------------------------------------------------

THETechnoid(a)home.com wrote: Hi I know of one other case that is similar to this. I don't recall the printer type but it was used with an apple. When the computer was turned on first, the input devices would latch up on the printer when it was powered up. In his case, if he turned on the printer first and then the computer, all worked fine. Another thing to look for is the line that has 5 volts on it. It may be connected at both ends, to both supplies. This would be bad because the supply with the higher voltage will try to power both units. These are the two things that I can think of to look for. Dwight