RS-485 wiring, step by step

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[OFFICIAL POST] EEDIY Team (official)

1. Use twisted-pair cable for A and B.
2. Connect devices one after another in a line (a “daisy chain”), not in a star.
3. Terminate both ends: with 120 ohm cable, a 120 ohm resistor at each end is common.
4. Use failsafe biasing (often built into the transceiver) so an idle bus reads cleanly.
5. If nothing answers, try swapping A and B. Vendors label them differently.

Sources:

• Texas Instruments, The RS-485 Design Guide (SLLA272): https://www.ti.com/lit/pdf/slla272

EEDIY Team (official)

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