NTBB25GA Nortel Norstar 6 Port Fiber Combo Expansion card
Norstar NTBB25GA 6 Port Slim Fiber Combo Card Feature Highlights: The Norstar 6 Port Combo expansion card is both a Service Card (T-1 Clock Controller) and a 6 Port Expansion card. It allows you to connect up to six expansion modules and a T-1 card to your Norstar Modular ICS Cabinet.