Patent ID: 7856183

Claim:
A channel card for an optical WDM signal transmission device for use in a network node having a local side and a remote side, the channel card comprising: a) a first holding device assigned to the local side of the network node, the first holding device adapted to be equipped with a local-side transceiver unit, and having an internal transmitting port connection and an internal receiving port connection which are adapted to connect to the respective transmitting or receiving ports of the local-side transceiver unit; b) two additional holding devices, which are both adapted to be equipped with a respective remote-side transceiver unit, and which each have an internal transmitting port connection and an internal receiving port connection, which are adapted to connect to respective ports of the remote-side transceiver units; c) a signal switching unit that has six connecting ports, wherein each connecting port is respectively connected to one of the internal transmitting port connections or receiving port connections of the first holding device or of the two additional holding devices; d) wherein the signal switching unit consists of three four-port switching units, each with two internal ports for connecting the four-port switching units among one another, and each with two external ports realizing the six connecting ports; e) wherein the signal switching unit physical design and control circuitry are constructed to allow control such that it is defined for each of the internal receiving port connections whether and to which selected internal transmitting port connection, or multiple selected internal transmitting port connections, the respective internal receiving port connection is connected; f) wherein the signal switching unit physical design and control circuitry are constructed to allow control such that the internal receiving port connection of a selected remote-side holding device is connected to the transmitting port connection of local-side holding device, and the internal receiving port connection of local-side holding device is connected to the transmitting port connection of the selected remote-side holding device; g) wherein the signal switching unit physical design and control circuitry are constructed in such a manner to realize a protection function in that the internal receiving port connection of local-side holding device is connected to the transmitting port connection of a second, nonselected remote-side holding device; h) wherein the signal switching unit is adapted to be controlled such that the normally open internal receiving port connection of the second, nonselected remote-side holding device is connected in protection operation to transmitting port connection of local-side holding device, in such a manner as to cause a switch from normal operation to protection operation if a signal can no longer be detected at the internal receiving port connection of the selected remote-side holding device.