The following bit significant indicators define the SONET interfaces that are supported by the transceiver. The defined identifier values are: Bits 0-1: Reserved Bits 2: I-64.5 - 1550 nm, 25 km, SM, IO Bits 3: I-64.3 - 1550 nm, 25 km, SM, IO Bits 4: I-64.2 - 1550 nm, 25 km, SM, IO Bits 5: I-64.2r - 1550 nm, 2 km, SM, VSR Bits 6: I-64.1/VSR2000-2R1/P1I1-2D1 - 1310 nm, 2 km, SM, VSR Bits 7: I-64.1r/VSR600-2R1 - 1310 nm, 0.6 km, Laser-MM Fibre-SM, VSR Bits 8: Reserved Bits 9: S-64.5b - 1550 nm, 40 km, SH Bits 10: S-64.5a - 1550 nm, 40 km, SH Bits 11: S-64.3b Bits 12: S-64.3a - 1550 nm, 40 km, SM, SH Bits 13: S-64.2b - 1550 nm, 40 km, SM, SH Bits 14: S-64.2a - 1550 nm, 40 km, SM, SH Bits 15: S-64.1 - 1310 nm, 20 km, IO Bits 16-17: Reserved Bits 18: G.959.1 P1L1-2D2 - 1550 nm, SM, 80 km, LH Bits 19: L-64.3 - 1550 nm, 80 km, LH Bits 20: L-64.2c - 1550 nm, 80 km, LH Bits 21: L-64.2b - 1550 nm, 80 km, LH Bits 22: L-64.2a - 1550 nm, 80 km, LH Bits 23: L-64.1 - 1310 nm, SM, 40 km, SH Bits 24-28: Reserved Bits 29: V-64.3 - 1550 nm, SM, 120 km, VL Bits 30: V-64.2b - 1550 nm, SM, 120 km, VL Bits 31: V-64.2a - 1550 nm, SM, 120 km, VL.