The Soneplex Single Fiber Quad Loop Extender (WQLX) module converts four multiplexed DS1 signals into an optical DS2 using wave division multiplexing (WDM) optics. Similar to ADC’s Quad Loop Extender (QLX), the WQLX transports the signal over single mode fiber, but uses only one fiber instead of two. The same module is also used at the remote end to convert the optical DS2 back into four DS1s at the customer premises.