US Patent 7451339 Pulse-per-second attachment for STP

A time synchronization apparatus, method and system are provided. In one aspect, the apparatus comprises at least a time of day clock, a first port operable to receive at least first time information using a first time protocol, a second port operable to receive at least second time information using a second time protocol, a third port operable to receive at least a timing signal, and a time stamp register operable to at least capture current value of the time of day clock upon receipt of the timing signal from the third port or the first time information from the first port or combination thereof.