The following bit significant indicators define the XFP device technology: Bits 0: 0-Transmitter not Tunable 1-Transmitter Tunable Bits 1: Detector Type: 0-PIN detector 1-APD detector Bits 2: Cooled transmitter Bits 3: Wavelength control: 0-No wavelength control 1-Active wavelength control Bits 4-7: Transmitter technology: 0000b 850 nm VCSEL 0001b 1310 nm VCSEL 0010b 1550 nm VCSEL 0011b 1310 nm FP 0100b 1310 nm DFB 0101b 1550 nm DFB 0110b 1310 nm EML 0111b 1550 nm EML 1000b Copper or others 1001b 1550 nm tunable 1111b-1001b Reserved.