> From: Charles Morris > Is there any standard pinout for 20 ma current loop using a DB-25 > connector, analogous to the well-documents RS-232 serial interface? > ... > Or would you recommend I use a different connector entirely? .. Maybe a > Jones 4-pin would make more sense.
I've never heard of people using DB25 for 20mA, at least historically, contemporaneous with its widespread actual use. E.g. DEC universally used 'flat' 8-pin Mate-n-Lok connectors for 20mA serial connections. Although I have the part numbers for both the male and female 8-pin shells, they are no longer in production, and are getting hard to find. Nothing precludes us from establishing a spec for 20mA via a DB25, of course - especially if a set of pins can be found whih will not cause damage if such a connector is plugged into an EIA connector by accident. As 'idiot proof' engineering, I'd be inclined to use some other connector (no suggestion from me as to what), but I can understand that people might prefer to use DB25 (which everyone has, and are easy to find). Noel