The BTRS-77120C-1590G series is high performance module for single fiber communications by using 1590 nm transmitter and 1510 nm receiver. A guaranteed minimum optical link budget of 31 dB is offered which can correspond to a link distance of over 120 km (assuming worst case fiber loss of 0.22 dB/km). The transmitter section uses a multiple quantum well 1590 nm DFB laser and is a class 1 laser compliant according to International Safety Standard IEC 60825. The receiver section uses an integrated 1510 nm detector preamplifier (IDP) mounted in an optical header and a limiting post-amplifier IC. A PECL logic interface simplifies interface to external circuitry. Signal Detect with LC-TTL is used.