2 x POTS Extender RJ11 Telephone and Gigabit Ethernet Over Fiber Optic - 10/100/1000Mbps RJ45 Over Fiber Optic Extender, Universal Single Mode 20Km(12.4 mi), Multimode 500m(0.31 mi),A Pair.

Extend PCM Voice Telephones and Network signal: 2 Independent telephone lines + 1 Gigabit Ethernet (10/100/1000 Mbit/s) port through same fiber optic cable to far end. Suitable for Both Fiber Types (Single-mode and multimode). Single-mode fiber for a long distance up to 20 km(12miles), Multimode fiber for a distance up to 500m(0.31miles)
Support Called id, Ring and Fax function, No Delay Transmission and Protocol Support: Unlike VoIP products - these converters transmit signals directly over fiber cables, thus offering NO DELAYS, plus support for fax & legacy applications that is not supported by VoIP lines.
With our Telephone over Fiber extender you can get faster speeds, less signal degradation, longer distance data transfer, better reliability, and more flexibility. Using a fiber optic cable can decrease costs over time because of the durability and reliability of the fiber cables. Fiber optic cables carry a low rate of bit error due to the fiber being highly resistant to electromagnetic interference.
Compact design. Sturdy Metal outer box, Bilateral heat dissipation make working life longer. LEDs for power supply and optical fiber link, data status indication can monitor the operating status of the system.
Simple to Install, Plug and Play. Note: the P1 & P2 is usable. P3 & P4 is useless (empty).