Abstract: The present invention provides shared communication medium capability to the plethora of computer devices, like the PCCAs, that normally are able to communicate with other devices via dedicated point-to-point links, e.g., via the practically universal RS-232 ports. It allows the sharing of the communication medium in a dynamic fashion depending on the instantaneous traffic demands by the various communicating devices. It further allows the emulation of point-to-point links over the shared communications medium in such a way that applications running on a PCCA use the shared medium transparently. Thus, this invention enables applications designed to operate over a point-to-point connection to operate over the shared medium without any modifications of the applications or the point-to-point devices.

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.