OPTICAL LINE TERMINATING DEVICE

PROBLEM TO BE SOLVED: To provide an optical line terminating device which can block the signal output of an optical line terminating device related to troubles and can dissolve a communication failure without the need for much labor and high costs.SOLUTION: An optical line terminating device 40 performing two-way communication with a broadcast center comprises: an optical transmitting/receiving terminal 41 as optical signal receiving means for receiving an optical signal; a PD 42 which converts the optical signal received by the optical transmitting/receiving terminal 41 into an electric signal; an electrical transmitting terminal 43 which transmits the electric signal converted by the PD 42; an electrical receiving terminal 44 which receives the electric signal; an LD 45 which converts the electric signal received by the electrical receiving terminal 44 into an optical signal; the optical transmitting/receiving terminal 41 as optical signal transmitting means for transmitting the optical signal converted by the LD 45; and an opening/closing switch 49 for blocking the transmission of the optical signal when it is determined that there is failure in an abnormality determining section 48a for determining the presence or absence of a failure of a device such as the optical line terminating device 40.