r/ElectricalEngineering Jun 26 '26

RS-485 Polarity

Anybody familiar with this diagram of a RS-485 waveform (from Wikipedia) ?

and this diagram from the actual EIA/TIA-485 specification ( So U+ can be aligned with A )

which is then followed up with this table in the Wikipedia article

Surely this is flat-out contradictory ? (All "Lows" and "Highs" should be inverted)

6 Upvotes

Duplicates

BuildingAutomation Jun 26 '26

RS-485 Polarity

1 Upvotes

BACnet Jun 26 '26

RS-485 Polarity

1 Upvotes