Patent ID: 7873073

Claim:
An interworking device for distributing reference timing between at least two different communication networks, the interworking device comprising: at least one first communication interface operable to communicate with a first communication network, the first communication network operating using a first communication protocol at a first clock frequency of a first clock signal; at least one second communication interface operable to communicate with a second communication network, the second communication network operating using a second communication protocol at a second clock frequency of a second clock signal; a client generic framing procedure/optical transport network (“GFP/OTN”) mapping block in communication with the first communication interface and the second communication interface, the client GFP/OTN mapping block converting first data in the first communication protocol at the first clock frequency recovered from a signal from the first communication network to second data in the second communication protocol at the second clock frequency, and converting third data in the second communication protocol at the second clock frequency recovered from a signal from the second communication network to fourth data in the first communication protocol at the first clock frequency; at least one hybrid synchronous equipment timing source, the hybrid synchronous equipment timing source: deriving the first clock signal from the second clock signal when converting data from the second protocol to the first protocol and deriving the second clock signal from the first clock signal when converting data from the first protocol to the second protocol; and at least one switch communicatively coupled to the client GFP/OTN mapping block and communicatively coupled to the at least one hybrid synchronous equipment timing source, the switch selectively providing a reference timing signal to the client GFP/OTN mapping block.