Relay protective optical fiber digital interface device

The invention relates to a relay protective optical fiber digital interference device, which comprises a switching value input circuit, a switching value output circuit and two central processing units (CPUs), wherein the output end of the switching value input circuit is connected to input ports of the two CPUs respectively; the output ends of the two CPUs are connected to the input end of an AND gate circuit; the output end of the AND gate circuit is in control connection with the switching value output circuit; each CPU comprises a transmission part and a receiving part; signals input into each CPU channel are processed by a delay judging module, a coding and framing module and a transcoder module of the transmission parts, and transmitted to a photoelectric conversion module; and the CPUs receive the signals from the photoelectric conversion module, process the signals by a code pattern inverse transformation module and a de-framing and decoding module of the receiving parts and output the signals by the output circuit. The relay protective optical fiber digital interference device adopts the two CPU and the two channels, realizes the increasing of transmission time and great improvements on safety and reliability.