Patent ID: 7414965

Claim:
A network element comprising: first and second redundant signal paths carrying first and second redundant signals, respectively; a first and second selectors for selecting either of the two redundant signals as active; first and second transition monitors coupled to the first and second signal paths, respectively; and first and second frame monitors for monitoring said first and second signals, respectively, for the presence of a predefined bit pattern, wherein said first selector is controlled by the transition monitors and said second selector is controlled by the frame monitors, wherein said transition monitors monitor said first and second signals for bit level transitions; and in that said first selector is controlled by the transition monitors to alter selection in the event that the selected signal does not contain bit level transitions while the non-selected signal does, and wherein said signals appear to be valid if said predefined bit pattern is detected and wherein changing selection from the currently selected signal to the other signal according to detection of bit level transition is enabled only, if both signal copies appear to be valid.