As mentioned, it allows an attendant to put discrete trunk groups in NIGHT mode as opposed to the entire system. It's especially useful if you have more than one tenant on the system, or groups within a company that have different working hours.

Look in the ADIX tech manual in the Attendant section for actual keystrokes.

Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.