The LXT6155 is a high speed fully integrated transceiver designed for 155 Mbps SDH/SONET/ ATM transmission system applications. The LXT6155 provides a LVPECL interface for fiber optics modules, and a CMI interface for coax cable drive. These circuits are implemented using Level One's proven low power 3.3V CMOS analog and digital circuits. The transmitter incorporates a parallel-to-serial converter, a frequency multiplier PLL, CMI line encoders, and line interfaces for both coax cable and optical fiber. The receiver incorporates an adaptive equalizer, a clock recovery PLL, Loss of Signal (LOS) detector, CMI and NRZ decoders, a serial-to-parallel converter, and an SDH/SONET frame byte detector/aligner. At the system interface, the LXT6155 offers both parallel 8-bit and serial differential interfaces. The LXT6155 also operates in either Hardware stand-alone mode or Software mode. Software mode is controlled by a serial microprocessor (P) to program formats and operating/test modes.