The Allied Telesis SBx81GC40 line card provides 40 Gigabit interfaces through 20 CSFP (Compact SFP) slots. Each CSFP module is equipped with two independent Gigabit Bidirectional Optical interfaces for a total of 40 Gigabit Optical Links. The ability to aggregate a large number of fiber interfaces within a single module is an excellent solution for high density fiber environments. The SBx81GC40 line card can be equipped with the Allied Telesis CSFP modules AT-SPBD20Dual-14 (20 km) and AT-SPBD40Dual-14 (40 km).