Bus termination missing
▲ warningsi/termination-missing
What it looks like
RS-485 declared on A/B, but no ~120 Ω termination bridges the pair. An unterminated bus reflects every edge — works on 10 cm of bench wire, garbles data on a real run.
What it checks
For nets declared as a terminated bus class (RS-485 and friends), verifies a termination resistor of roughly the right value actually bridges the pair.
Why it matters
A transmission line without its characteristic termination reflects every edge back down the cable. The cruel part is that it works on the bench — short wires, slow edges — and fails at installation length.
How to fix it
Add the termination resistor (typically 120 Ω for RS-485) at the far end of the bus. If the design intentionally relies on a receiver's built-in termination, declare that part where the check can see it.
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