Patent ID: 7836208

Claim:
A communication network system comprising: at least two terminals, including: a first terminal including a first standard terminal interface, and a second terminal including a second standard terminal interface and a redundant terminal interface; a series of links to transmit information, including: a standard link connected to said first standard terminal interface, a critical standard link connected to said second standard terminal interface, and a redundant link connected to said redundant terminal interface; a series of coupler interfaces, including: a redundant coupler interface connected to said redundant link, including a first means for blocking information received from said redundant link until receiving an enable signal, a first standard coupler interface connected to said critical standard link comprising: means for detecting a link fault in said critical standard link, and a second means for blocking information received from said critical standard link in response to a detection of the link fault in said critical standard link, and a second standard coupler interface connected to said standard link; a coupling device connected to said first and second standard interfaces and said redundant coupler interface, said coupling device exchanging information between said coupler interfaces; and means for controlling said first means for blocking, wherein said means for controlling send an enable signal to said first means for blocking in response to said detection of the link fault in said critical standard link.