Abstract: A fiberoptic communications method is presented which allows an open-link condition on one link of a multi-link fiberoptic connection to be propagated to other links of the connection while satisfying the Open Fiber Control safety standard. Each link comprises a duplex link and at least one optical repeater is employed. The at least one optical repeater is adapted to propagate an open-link condition in one link of the multiple duplex links between the links of the fiberoptic connection. Propagating the open-link condition can be accomplished using an out band signal, an electrical wrap mode, or a hybrid approach using both an out band signal and electrical wrap mode. Automatic propagation of a closed-link condition is provided once the originally opened link is closed.

Abstract: A fiberoptic communications computer program product is presented which allows an open-link condition on one link of a multi-link fiberoptic connection to be propagated to other links of the connection while satisfying the Open Fiber Control safety standard. Each link comprises a duplex link and at least one optical repeater is employed. The at least one optical repeater is adapted to propagate an open-link condition in one link of the multiple duplex links between the links of the fiberoptic connection. Propagating the open-link condition can be accomplished using an out band signal, an electrical wrap mode, or a hybrid approach using both an out band signal and electrical wrap mode. Automatic propagation of a closed-link condition is provided once the originally opened link is closed.

Abstract: Efficient methods for rerouting failed channels on to spare channels in a multichannel transmission system are described. One method uses a minimal amount of rerouting to reroute all the channels if one or two line cards fail.

Abstract: Efficient methods for rerouting failed channels on to spare channels in a multichannel transmission system are described. One method uses a minimal amount of rerouting to reroute all the channels if one or two line cards fail. Another set of methods reroute up to two failed channels on to spare channels in the event of channel failures. With this method only the failed channels are rerouted. However the failed channels may have to be routed through a slightly larger, but minimal, number of additional hops than with the first method.

Abstract: A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs.

Abstract: Efficient methods for rerouting failed channels on to spare channels in a multichannel transmission system are described. One method uses a minimal amount of rerouting to reroute all the channels if one or two line cards fail.Another set of methods reroute up to two failed channels on to spare channels in the event of channel failures. With this method only the failed channels are rerouted. However the failed channels may have to be routed through a slightly larger, but minimal, number of additional hops than with the first method.