The ADAM-6542 adopts WDM technology that increases the information carrying capacity of fiber via multiplex transmit and receive signals at different wavelengths on the single strand cable. The WDM technology is implemented in couples. One site is installed ADAM-6542/W15 which transmit channel is 1550nm and receive channel is 1310nm. The other site is installed ADAM6542/W13 which transmit channel is 1310nm and receive channel is 1550nm. Both transmit and receive channels of ADAM-6542/W15 and ADAM-6542/W13 are multiplexed to a single strand cable. You can save half cabling cost when you use ADAM-6542/W15 and ADAM-6542/W13 instead of your original dual fiber converter.