Patent ID: 7912375

Claim:
An optical transceiver that is removable from a host device and performs an optical transmitting and receiving operation (i) receiving an electrical signal from the host device, converting the electrical signal received into an optical signal, transmitting, externally, the optical signal converted, and (ii) receiving an external optical signal, converting the optical signal received into an electrical signal, and transmitting the electrical signal converted to the host device, when the optical transceiver is attached to the host device, comprising: a first memory that is a volatile memory; an external interface that writes information received from the host device in the first memory, reads the information written in the first memory in response to an external command, and transfers externally the read information, wherein the information includes at least one of information indicative of an operation start date, when the optical transceiver starts optical transmitting and receiving operations, and information indicative of an operation termination date, when the optical transceiver terminates the optical transmitting and receiving operations; a second memory that is a nonvolatile memory; means for copying the information written in the first memory and writing the information copied in the second memory; and means for copying the information written in the second memory and writing the information copied in the first memory when power supplied to the first memory is stopped and then restarted.