What This Product Does TL-FC111PB-20 is a 10/100 Mbps media converter with 802.3af PoE output, providing 1× 10/100 Mbps PoE RJ45 port and 1× 100 Mbps SC fiber port, which can convert between electrical and optical signals. With up to 20 km fiber transmission distance and 802.3af PoE output, the media converter is designed to address the needs of flexible long-range surveillance deployment with optical fibers. It provides an economical path towards extending the distance of an existing network. How This Product Works TL-FC111PB-20 adopts WDM (wavelength division multiplexing) technology, helping send and receive data at a distance of up to 20 km with only a single mode fiber, which saves half of the cable deployment cost for customers. TL-FC111PB-20 transmits data at 1310 nm wavelength and receives data at 1550 nm wavelength on optical fiber. Therefore, the terminal device used in conjunction with the TL-FC111PB-20 should send data at a wavelength of 1550 nm and receive data at a wavelength of 1310 nm. TP-Link another media converter TL-FC111A-20 is one of the products that can cooperate with TL-FC111PB-20. Other Features Besides, this media converter can be used as a standalone device (no rack required) or used with TP-Link's TL-FC1420 rack for auto MDI/MDI-X in TX port in which duplex mode is automatically negotiated.