israel@mitisft.Convergent.COM (Paul Israel) (11/17/90)
I'm designing an interface board which needs to talk to two different parallel printers, a Centronics-compatible (ala Epson) and a Data Products interface. Unfortunately, neither interface is an officially sanctioned standard, so I can't find a comprehensive specification for either interface. By sorting through several different manuals for various printers, I've managed to piece most of it together, but I still lack some vital information: 1) What sort of termination is required for the drivers? For the receivers? Especially for the Data Products port. It looks like Data Products uses 470/470 ohm terminators, which seems strange, as I would normally expect something like 220/330. 2) What is the default polarity of interface signals for Data Products interfaces? The one DP manual that I found seems to suggest that polarity is programmable, but I can't tell what the standard setting is, or which signals are affected. Does the programmable polarity affect the data bus as well? If polarity is set to true high, then don't the terminators cause the control signals to appear active if the host system is off? 3) Can anybody reccommend a good source book for this kind of information? Preferably something all-inclusive of data such as signal names and definitions, timing requirements, signal driver and receiver requirements, etc. (Not much, jus the whole world...) I'M SO CONFUSED! Somebody help me, help me please! Please email responses directly. Thank you verra, verra much. -- Paul Israel Renegade Systems, 434 South Bernardo Ave, #2 Sunnyvale, CA 94086 Disclaimer: "Who, me? I wasn't even there!" ctnews!mitisft!hamster!israel