Default behavior on startup?

[ranzbak]

What light behavior is expected on startup of the traffic light before configuration / communication?

For example, no light at all, or blink orange ?

[Stoneshop]

Suggestion:

• on powerup a brief selftest, indicated by lighting up LEDs on the central horizontal line red or green as applicable
• on selftest pass and not having established communications with its segment partner unit, a moving yellow dot on the central horizontal line
• after having established a link with its designated partner, the pair can start running in dumb mode. As soon as the central controller is up and has established comms with both units, it can start controlling them as required.

The unit ID must be present on a physical tag so it's not necessary to display them in some way during startup.

[ranzbak]

The unit ID must be present on a physical tag so it's not necessary to display them in some way during startup.

I would say a sticker on the case indeed, actually a different requirement.