An apparatus includes multiple ports configured to be coupled to multiple optical fibers and to transmit first optical signals and receive second optical signals over the optical fibers. The apparatus also includes a signal source configured to generate a first additional optical signal for inclusion with the first optical signals. The apparatus further includes a signal detector configured to detect a second additional optical signal included with the second optical signals. In addition, the apparatus includes a switch configured to selectively couple the signal source to one of the ports. The switch is configured to couple the signal source to different ones of the ports in different configurations of the switch.