Abstract: Embodiments disclosed herein provide a hybrid fiber-copper access network in which a main OLT sends data to the DSLAMs via a plurality of point-to-point optical fiber connections. A standby OLT is provided which has a plurality of point-to-multi-point optical fiber connections to the DSLAMs. In the event of a failure, data can be sent to some of the DSLAMs via the standby OLT and the point-to-multi-point optical fiber connections. Following the rectification of the fault, the network can revert to its normal state and transmit data to the DSLAMs via the main OLT and the plurality of point-to-point optical fiber connections.

Abstract: An optical line terminal for use in a multi-wavelength network to operatively connect via a PON port by a first connection to a first network node and to operatively connect via the PON port by a second connection to a second network node, the optical line terminal being configured to operate under first network conditions by sending no data via the second connection, and to operate under second network conditions by sending data via the second connection.

Abstract: An optical line terminal for use in a multi-wavelength network to operatively connect via a PON port by a first connection to a first network node and to operatively connect via the PON port by a second connection to a second network node, the optical line terminal being configured to operate under first network conditions by sending no data via the second connection, and to operate under second network conditions by sending data via the second connection.

Abstract: Embodiments disclosed herein provide a hybrid fiber-copper access network in which a main OLT sends data to the DSLAMs via a plurality of point-to-point optical fiber connections. A standby OLT is provided which has a plurality of point-to-multi-point optical fiber connections to the DSLAMs. In the event of a failure, data can be sent to some of the DSLAMs via the standby OLT and the point-to-multi-point optical fiber connections. Following the rectification of the fault, the network can revert to its normal state and transmit data to the DSLAMs via the main OLT and the plurality of point-to-point optical fiber connections.

Abstract: A protected passive optical communications system includes terminals, a main head end, and a back up head end allowing communication with the terminals when a fault occurs. The main and back up head ends transmit frames that include header and payload portions to the terminals. The main head end normally transmits control instructions in the header and user data in the payload. The back up head end, in response to a fault, transmits control instructions in the payload, and a control message in the header. The control message indicates control instructions in the payload. If a control message is in the header, each terminal interprets the payload as control instructions for changing operational attribute(s) of a terminal. If a control message is not in the header, each terminal interprets the payload as user data that it forwards to external user(s) external based on an address from the user data.

Abstract: A protected passive optical communications system (10), having a plurality of terminals (14), a main head end (22) for communicating with the terminals (14) in an operational state, and, a back up head (37) end arranged to allow communication with the terminals (14) in the event of a fault, the main head end (22) and the back up head end (37) each being operable to transmit a sequence of frames for communicating with the terminals (14), each frame having a header portion and a payload portion, the main head end (22) being arranged, in normal operation, to transmit control instructions in the header portion and user data in the payload portion of each frame, the back up head end (37) being arranged, in response to a fault, to transmit control instructions in the payload portion of a frame, and a control message in the header portion of that frame, which control message is indicative of the presence of control instructions in the payload portion, the terminals being responsive to the control message, such that: