The FOS-79710 Fiber Optic Switch Module is designed for high return loss, low insertion loss, and excellent stability. Transparent to signal formats and bandwidths, this optically passive fiber optic switch is bi-directional in operation and offers a choice of timed, random, sequential or triggered switching modes. In the FOM-7900B System Mainframe, the front panel or GPIB-accessible command set controls the FOS-79710 Fiber Optic Switch Module. A single channel input can go to any of the 4 outputs via the FOM-7900B control panel. A “blocking” position switches the input to a zero-reflection terminaton. The user can define and initiate sequential switching through an external trigger, or by defining a switch interval time.