Patent ID: 7295776
Filing Date: 2007-11-13
Classification: H04L

Abstract:
1. An optical LAN device including a master node and a plurality of slave nodes interconnected by an optical fiber cable for configuring a network, the network including a plurality of optical bypass transmission lines each corresponding to an associated one of the slave nodes, each of the optical bypass transmission lines bypassing the corresponding slave node, wherein each of the slave nodes includes: a light sending portion controlled to flash for generating an optical signal transmitted to the network; and an optical cutoff circuit for forcibly switching the light sending portion to a turned off state when the slave node fails such that the corresponding light sending portion is maintained in a turned on state, wherein each of the light sending portions includes a light emitting element and a switching element for driving the light emitting element, the light emitting element being turned on when the switching element is turned on and turned off when the switching element is turned off, the optical cutoff circuit forcibly switching the switching element from a turned on state to a turned off state when the corresponding slave node fails such that the switching element is maintained in the turned on state, and wherein each of the slave nodes includes a controller outputting a drive signal to the corresponding switching element for controlling the switching element, and, when the controller fails and continuously outputs the drive signal for maintaining the switching element in the turned on state, the corresponding optical cutoff circuit invalidates the drive signal outputted by the controller.