The TP-Link TL-SM321B (SM321B) is a high-performance 1000Base-BX WDM Bi-Directional SFP transceiver module designed to optimize fiber optic connections by utilizing WDM (Wavelength Division Multiplexing) technology. It enables simultaneous transmission and reception of data over a single strand of single-mode fiber, drastically reducing fiber infrastructure costs for point-to-point links.

Key features include a data transmission rate of 1.25 Gbps, compliant with the IEEE 802.3z standard, and hot-swappable functionality to facilitate easy installation and maintenance without disrupting network operation. The transceiver uses distinct wavelengths for transmission (1310 nm) and reception (1550 nm), working in tandem with a complementary module such as the TL-SM321A to establish robust bidirectional communication.

This module supports LC/UPC simplex connectors, operates on a 3.3 V power supply, and is compatible with 9/125 µm single-mode fiber. It offers a typical maximum reach of up to 10 km, with some hardware revisions extending distance up to 20 km. The TL-SM321B supports Digital Diagnostic Monitoring (DDM) for real-time status monitoring and adheres to SFP MSA industry standards.

Engineered for reliability, it operates effectively within a temperature range of 0 to 70 °C and carries FCC and CE certifications. The product includes a limited 3-year warranty, providing users with long-term dependability and support.

Ideal for network administrators seeking cost-effective, efficient, and scalable fiber optic solutions, the TP-Link TL-SM321B module is well-suited for use in switches, routers, media converters, and other fiber networking equipment.