The CrewCom 4+4 Control Unit is the foundational element of the CrewCom system and establishes the CrewNet-based infrastructure while also providing external connections to common established intercom systems. By design, the CU contains no radio and is frequency agnostic and can therefore control and monitor any device across CrewNet regardless of radio frequency bands being utilized. With the combination of CrewCom Radio Transceivers, each CU supports up to 50 Radio Packs, 18 Normal mode and 32 High Density mode, across all available RF bands.