Norstar NTBB20FB 12x0 Fiber Trunk Module allows for more trunk lines to be added to the MICS Norstar control unit. It connects via an expansion port on 2 port or 6 port fiber expansion cards. Fiber Trunk Modules may be connected to the Modular ICS by a fiber cable. Each Fiber Trunk Module holds up to three Trunk Cartridges. New + 2 year warranty.