MCI has begun trials of a system from Hitachi Telecom that enables the complex restoration of high-speed transmission routes on optical networks. The MCI-Hitachi application employs five optical cross-connect systems deployed at various nodes in MCI's fiber optic network in Dallas. The trial covers ring and mesh route topologies operating at two different transmission rates. It also is compatible with existing protection schemes and can simultaneously restore wavelength division multiplexed signals. Optical cross-connects require integrating a number of small, very fast optical switch elements, along with monitoring and control circuits. Switching from failed optical routes to restoration fibers must be accomplished automatically and quickly, often requiring use of multiple restoration paths.