WTD RTXM159-400 SFP Transceiver

The WTD RTXM159-400 is a hot-pluggable SFP (Small Form-factor Pluggable) optical transceiver module designed for 622 Mbps SDH/SONET applications. It provides a single bidirectional optical interface operating at the nominal line rate of 622.08 Mbit/s (STM-4/OC-12).This module operates at a nominal wavelength of 1310 nm using a Fabry-Perot (FP) laser transmitter and a PIN photodiode receiver. It is optimized for single-mode fiber (SMF 9/125 µm) with a typical transmission distance of up to 15 km. The optical link budget supports reliable performance with low bit error rates (better than 10⁻¹²) over the specified reach. Transmitter average output power is typically in the range of -15 dBm to -8 dBm, while receiver sensitivity reaches down to approximately -28 dBm or better, providing sufficient margin for intermediate-reach links.

The RTXM159-400 complies with the SFP MSA and relevant ITU-T G.957 / Telcordia GR-253 standards for STM-4 IR-1 / S-4.1 interfaces. It supports framed SDH STM-4 and SONET OC-12 signals, including section, line, and path overhead processing when installed in a compatible host platform. The module enables transport of concatenated payloads or grooming of lower-rate tributaries through the system’s cross-connect functions.

Optical connectivity is realized through a duplex LC connector. Key operational features include Loss of Signal (LOS) detection and assertion, automatic laser shutdown (ALS) for Class 1 eye safety compliance, and digital diagnostic monitoring (DDM) compliant with SFF-8472. Real-time parameters such as transmitted and received optical power, laser bias current, temperature, and supply voltage are reported to the network management system.

The module uses the standard 20-pin SFP electrical interface with a single +3.3 V power supply and low power consumption (typically below 1 W), making it suitable for high-density port configurations in SDH/SONET equipment. It supports hot-swap insertion and removal without service disruption in redundant setups. Environmental specifications include a commercial operating temperature range of -10°C to +70°C, high humidity tolerance, and built-in ESD protection.

This SFP transceiver is primarily used for intermediate-reach 622 Mbps optical links in SDH/SONET add-drop multiplexers, terminal multiplexers, or as a tributary interface in multiservice transport platforms. It ensures reliable optical transport with low jitter and high signal integrity over single-mode fiber up to 15 km.

The module integrates seamlessly with network management systems for remote provisioning, performance monitoring (including BIP error checking and signal quality thresholds), and alarm reporting. Installation requires standard fiber optic cleaning procedures, correct Tx/Rx fiber polarity, and adherence to minimum bend radius guidelines for duplex LC patch cords. The WTD RTXM159-400 offers a reliable, cost-effective solution for 622 Mbit/s optical transport over single-mode fiber in legacy and current telecom infrastructures.