Somewhere deep in the EIA 485 (and 422) specification is wording suggesting the DC resistance between transmitter return and receiver return not exceed some value. This value was somewhere close to 200 ohms maximum. This certainly implies your correct statements 2 wire really means 3.
Time...
Highroller10 wrote...
"IEEE withdrew IEEE STD 200/ANSI Y32.16 covering formation and application of reference designations for electronic equipment, which applied to most military electronics. Did any document take its place as regards section 8 requiring marking of ref designations on...
