US Patent 7233738 Protection switching architecture and method of use

A protection switching architecture is used in a telecommunications system such as a wavelength division multiplexed (WDM) telecommunications system to replace a failed transmission line or a failed wavelength processing device. A spare wavelength processing device transmitter replaces a failed service wavelength processing device transmitter. A spare transmission line replaces a failed service transmission line. A spare wavelength processing device receiver monitors the optical signals, one wavelength at a time, on either the spare transmission line or the service transmission line and replaces one of the service wavelength processing device receivers. Wavelength selection equipment routes either the service transmission line or the service transmission line to the service wavelength processing device receivers and selects wavelengths to be monitored by the spare wavelength processing device receiver.