20‑Call Audio Master Station. The NIM-20B supports up to 20 door stations, sub stations, and ceiling speakers. It provides Selective Call, Group Call, and All Call. The NIM-20B has a handset for privacy.

The NIM Series is a Lamp Memory Intercom supporting a single master station and up to forty sub stations. Calls to the sub stations can be placed selectively or via All Call from the master station.