Abstract: An optical fiber transmission distribution assembly, wherein the assembly comprises at least a first splitter having a first split ratio of 1:x (where x is an integer) connected to optical drop cables leading to subscribers, and at least a second splitter having a second split ratio of 1:y (where y is an integer and is different from x), and transfer means whereby an optical drop cable connected to the first splitter can be transferred to receive split optical signals from the second splitter, thereby enabling the signal in the transferred drop cable to be further split by addition of a third splitter at a ratio of 1:p (where p is an integer), to provide p subscriber connection points each having a 1:p*y split ratio at the subscriber end of the transferred drop cable.

Abstract: A method for localizing an optical network termination in an optical access network including an optical line termination and a number of optical links.

Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: An optical transmission system is provided. The optical transmission system includes a user side optical repeater device (ORD), a central office side ORD, and wavelength multiplexing and wavelength de-multiplexing functions (MUX/DEMUX). The user side optical repeater device (ORD) is to be connected with a user side optical network unit (ONU), transmits data in two ways, and is used for wavelength division multiplexing (WDM). The central office side ORD is to be connected with a central office side optical line terminal (OLT), transmits data in two ways, and is used for WDM. The wavelength multiplexing and a wavelength de-multiplexing functions (MUX/DEMUX), are used for relaying between the user side ORD and the central office side ORD.

Abstract: A radio-over-fiber (RoF) hybrid wired/wireless transponder is disclosed that is configured to provide both wireless and wired communication between a hybrid head-end and one or more client devices. The hybrid transponder includes optical-to-electrical (O/E) and electrical-to-optical (E/O) conversion capability and is configured to frequency multiplex/demultiplex electrical “wired” signals and electrical “wireless” signals. The electrical wireless signals are wirelessly communicated to the client device(s) via a multiple-input/multiple-output (MIMO) antenna system within a cellular coverage area. The electrical wired signals are communicated to the client device(s) via a wireline cable that plugs into a wireline cable port on the transponder. The hybrid RoF system includes a hybrid head-end capable of transmitting and receiving wired and wireless optical signals, and an optical fiber cable that is optically coupled to the hybrid head-end and to at least one hybrid transponder.

Abstract: N optical transceivers are each connected to a respective electronic module in one-to-one relation such that a respective one electronic module controls a respective one optical transceiver. An electronic switch matrix provides cross-connect capability between the P redundant electronic modules and N electronic modules to the N optical transceivers. A system controller determines when an active N electronic module has failed, and configures the electronic switch matrix to switch a P redundant electronic module into the optical transceiver to which the failed electronic module was connected. A system switch module redirects traffic and routing information, under the direction of the system controller, from the failed module to the newly activated redundant module so that the redundant module assumes the functionality of the failed module.

Abstract: Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.

Abstract: A method for data processing in an optical network includes providing at least one main wavelength and processing a subcarrier modulation for the at least one main wavelength, wherein a portion of the subcarrier modulated signal is suppressed. An optical network component and a communication system having such an optical network component are also provided.

Abstract: A method and apparatus for providing passive optical networks with extended reach and/or splitting ratio are disclosed. For example, the optical network comprises a first optical line termination (OLT) device having a transceiver for sending and receiving optical signals. The optical network further comprises an optical extender box comprising at least one hybrid SOA-Raman amplifier, wherein the optical extender box is coupled to the first optical line termination device via a first standard single mode fiber section. Finally, the optical network further comprises an optical splitter coupled to the optical extender box via a second standard single mode fiber section.

Abstract: An optical communications system includes a MSAP and an optical transceiver mounted at the MSAP that communicates over an optical network to at least one optical network terminal (ONT). A first electronic module is operatively connected to the optical transceiver and configured to control the optical transceiver and mounted at the MSAP separate from the optical transceiver. A redundant second electronic module is supported within the MSAP and mounted separate from the optical transceiver. A Mux/Demux module interconnects and supports the first and second electronic modules to form an integral unit and mounted at the MSAP separate from the optical transceiver. The Mux/Demux module is configured to switch the second electronic module into communication with the optical transceiver upon failure of the first electronic module.

Abstract: The present disclosure generally pertains to an arrayed media converter (AMC) that has an array of Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) Optical Network Units (ONUs) for terminating an optical channel in the feeder or distribution portion of a telecommunication network. The ONU converts an optical signal from the optical channel into at least one electrical signal for transmission to a customer premises. Thus, the AMC serves as an interface between at least one WDM-PON link and at least one conductive connection, such as a twisted pair. In one exemplary embodiment, the AMC comprises a sealed housing that is environmentally hardened to protect the AMC from environmental conditions, including changes in weather. Such an AMC may be used to provide a robust, cost effective Fiber To The Curb (FTTC) solution, but the AMC may be used at other points within the network, if desired.

Abstract: Methods, systems, and computer-readable media provide for notifying an optical line termination (OLT) of a power failure. According to embodiments, a method for notifying an OLT of a power failure is provided. According to the method, a notification of a power failure at an optical network termination (ONT) is received. In response to receiving the notification, power is retrieved from a dedicated power storage unit dedicated to providing power for the transmission of a dying gasp alarm. The dying gasp alarm is transmitted to the OLT utilizing at least a portion of the power from the dedicated power storage unit. The dying gasp alarm notifies the OLT of the power failure.

Abstract: A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

Abstract: The present disclosure relates to a passive optical network (PON) and provides a method for maintaining the PON, the optical network unit (ONU), and the optical line terminal (OLT) to solve the problem of the ONU being in a constant light emitting state. The method of the present disclosure allows the OLT to determine whether the continuous seizure time of an upstream channel exceeds the preset threshold, and if so, detect the failed ONU that continuously seizes the upstream channel and use a control message or control signal to instruct the failed ONU to turn off power supply to its transmitting circuit.

Abstract: Consistent with the present disclosure, based on system requirements or in response to an increase in optical signal-to-noise level of an optical channel, such as a WDM channel, additional FEC bits are inserted into and replace selected data payload bits in each frame carried by the channel. The replaced data payload bits may then be transmitted in subsequent frames on the same channel. As a result, the transmitted frames have a reduced data payload rate, but a higher coding gain. Alternatively, the replaced data payload bits may be included in frames transmitted on another optical channel. In that case, the frames carried by the two channels typically have the same bit length or number of bits and may thus be compliant with the frame length requirements of G.709, for example. Preferably, the number of coding bits may be changed dynamically to obtain different coding gains.

Abstract: A method and apparatus for implementing a hybrid SOA-Raman amplifier in a central office in order to enable multiple passive optical networks to share one or more enhancement service sources, e.g., to share a source for a broadcast service are disclosed.

Abstract: A wavelength division multiplexer is provided by the present invention, which implements the wavelength division multiplexing and de-multiplexing of the optical signals in the basic and upgrade bands by reasonably arranging the filters and selecting the spectral properties of the filters, so that the existing time division multiplexing passive optical network (TDM-PON) can transmit the next generation passive optical network (NG-PON) simultaneously and the existing TDM-PON can be smoothly upgraded to the NG-PON, meanwhile, it provides the deployed TDM-PON with the subsequent network compatibility. The wavelength division multiplexer provided in the present invention can meet the high isolation requirement of the optical signals in working band with low cost, and takes both the isolation requirement and the optical network insertion loss requirement into account, thus it has high reliability, is easy to use and for system upgrade.

Abstract: A distribution node of a passive optical network (PON) comprises a first port for receiving a first optical continuous envelope modulated downstream data signal at a first wavelength (?C) from a first optical line termination unit (OLT1) and a second port for receiving a second optical continuous envelope modulated downstream data signal at a second wavelength (?L) from a second optical line termination unit (OLT2). A first converter (FBG-1) performs continuous envelope modulation-to-intensity modulation conversion of the first optical downstream data signal and forwards the converted first optical downstream data signal (?C) to the first group of optical network units (ONU1 . . . N). A second converter (FBG-2) performs continuous envelope modulation-to-intensity modulation conversion of the second optical downstream data signal and forwards the converted second optical downstream data signal (?L) to the second group of optical network units (ONUN+1 . . . 2N).

Abstract: A dynamic bandwidth allocation apparatus of a passive optical network detects guarantee agreement information of each transmission container (T-CONT) queue of at least one optical network unit (ONU) that is connected to the dynamic bandwidth allocation apparatus in order to dynamically allocate a bandwidth is provided. The dynamic bandwidth allocation apparatus sets a queue threshold according to a buffer size of each T-CONT queue of at least one ONU, and calculates a service level agreement (SLA) parameter of at least one ONU using guarantee agreement information and a queue threshold. The dynamic bandwidth allocation apparatus allocates a bandwidth for every frame of each ONU using each SLA parameter of at least one ONU.

Abstract: Systems and methods for enabling different network nodes of a network access system to share a backhaul communication link are disclosed. In one embodiment, the method includes: connecting a first modem to a first node of the network access system; connecting a second modem to a second node of the network access system; connecting the first modem to a first port of a splitter filter; connecting the second modem to a second port of the splitter filter; and connecting a backhaul communication link to a third port of the splitter filter, which is configured to multiplex signals transmitted by the modems onto the backhaul communication link, wherein the frequency spectrum of the signal transmitted by the first modem does not overlap substantially with the frequency spectrum of the signal transmitted by the second modem.

Abstract: The invention relates to improvements in or relating to modulation in an Optical Network, and to an apparatus, a method and a communications network for modulation in an Optical Network. An apparatus is arranged to receive a modulated optical signal comprising a carrier wavelength and first data. The apparatus is arranged to substantially erase the first data from the optical signal by performing an inversion operation on the modulated optical signal. The apparatus is arranged to receive second data and to modulate the carrier wavelength with the second data for onward transmission of the second data. The inversion operation comprises applying a signal comprising an inverse of the first data to at least a portion of the modulated optical signal. The signal may further comprise the second data such that the modulation of the carrier wavelength and erasure of the first data is performed in a single operation.

Abstract: A technique for forwarding downstream packets in a GPON comprising an OLT unit having a physical PON port connected to N Optical Network Termination (ONT) units by optical fibers. The physical PON port accommodates N individual virtual GEM ports terminated with the N ONT units (ONTs) which form N:1 service. The technique comprises assigning in the physical port of the OLT unit a virtual GEM port being a shared broadcast GEM port terminated with all the N ONTs of the N:1 service. Those downstream packets applied to the physical PON port, which would otherwise be flooded—such as broadcast packets or packets having unknown destination address—will now be forwarded only via the shared broadcast GEM port.

Abstract: A method and a device process data in an optical network. At least one dedicated time slot is used for transmitting time critical information from an optical network unit towards an optical line terminal. Due to the dedicated time slot, previous long delays in channel switching are decreased or substantially avoided.

Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data. Therefore, the complexity of the implementation of the RE is reduced, and the method is simple and effective.

Abstract: The longest possible sleep time is selected while data missing is prevented in a PON system by referring to the link speeds and the queue buffer capacities of an OLT and ONUs. The OLT calculates a first sleep time candidate based on a first link speed at which the OLT communicates with an upper network and the capacity of an unused area of a first queue buffer where downstream data is held for each of the destination ONUs. Each of the ONUs calculates a second sleep time candidate based on a second link speed at which each of the ONUs communicates with a communication terminal and the capacity of an unused area of a second queue buffer where upstream data bound for the OLT is held. The smaller sleep time is determined and used to change one of the ONUs to a sleep mode.

Abstract: In a PON system in which communication is performed at a plurality of types of transmission rate (L, M, and H) in an upstream direction from a plurality of terminals connected to a station apparatus through optical fibers, within a discovery period for allowing an unregistered terminal to be recognized by station apparatus, the terminal makes a discovery response at one type of transmission rate (L). With this configuration, station apparatus can wait for a discovery response with a receive function being allowed to support transmission rate (L).

Abstract: In a TDMA optical network, a clock data recovery module uses signal oversampling and preamble correlation together with enhanced performance modules to extract additional data from the upstream transmission signal. Information including duty cycle, ONT power estimation, signal noise and jitter can be extracted from the upstream signal using digital logic and used to tune network components and/or alleviate network conditions.

Abstract: A passive optical network system such that the power consumption can be reduced as much as possible according to the end-user traffic. An OLT uses the DBA function thereof and sequentially uses frequencies in ascending order of transmission rate in order to sequentially allocate bands to ONUs in ascending order of the requested bandwidth. At this time, a frequency to be allocated is selected so that the bandwidth allocated to each ONU is narrower than a maximum bandwidth through which transmission using the allocated wavelength is enabled. An OLT uses a grant area to specify the transmission timing of the secondary station and to inform the specified transmission timing to the secondary station. In addition, an area is set for storing information used to inform the secondary station of a new frequency to be used.

Abstract: It is necessary to completely remove overlapping of signals between plural PONs in order to make the PONs coexist. Accordingly, it is required to share or intensively manage bandwidth use conditions over an optical fiber that serves as a common band between plural systems. Therefore, transmission clocks should be synchronized with high accuracy between plural systems. A reference clock is provided from an external device or a representative OLT to the entire systems to perform clock synchronization between plural systems, so that the overall systems are synchronized by synchronizing each OLT with the reference clock. A hierarchical management method is selected that manages ONUs under the control of each OLT by managing band use information arranged for each OLT with respect to an external device or a representative OLT for sharing of bandwidth use conditions between plural systems.

Abstract: An optical access network (OAN) system is provided. In the system, a remote radio unit (RRU) receives and sends a wireless signal and implement conversion between the wireless signal and a first frequency signal; an optical network device receives and sends the wireless signal, and implement conversion between the wireless signal and the first frequency signal and conversion between the first frequency signal and a fiber transmission signal; an optical distribution network (ODN) connected to the optical network device transmits the fiber transmission signal; an optical line terminal (OLT) device receives and sends the fiber transmission signal, and implements conversion between the fiber transmission signal and a second frequency signal, conversion between the second frequency signal and a base band signal, and conversion between the base band signal and a signal of another standard protocol.

Abstract: In an access network using optical switches, communications between an OLT and ONUs are established without a photoelectric conversion performed at an optical switching unit. The OLT controls the downlink optical switch SW(DOWN) to sequentially select each ONU in slots arranged in a discrete manner, and transmits a Discovery Gate message. Upon receipt of the Discovery Gate message, each ONU consecutively transmits Register Request messages. The uplink optical switch SW(UP) sequentially switch signals from ONU#1 through ONU#128 in the slots arranged in a discrete manner, and outputs the signals to the OLT, Some of the Register Requests transmitted from the respective ONUs pass through the SW(UP), and reach the OLT. Based on the received Register Requests, the OLT determines the timing of transmission for the ONUS, and notifies the ONUS of the timing of transmission through a Gate message.

Abstract: An approach is provided for integrating one or more fiber switches in a passive optical network. A platform generates a command signal to control a splitter hub of a passive optical network, the splitter hub being configured to communicate with a plurality of optical network terminals that respectively serve a plurality of customer premises. The splitter hub includes a fiber switch configured to provide switching between one of a plurality of input ports and one of a plurality of output ports of the splitter hub.

Abstract: An optical line terminal includes the transmission rate control table for storing a minimum bandwidth for an emergency status for each of optical network units in addition to a maximum assigned bandwidth in a normal status. When a decrease in a supply power is detected, the optical line terminal calculates a transmission clock rate providing a minimum bandwidth required by each optical network unit with reference to the transmission rate control table. The optical line terminal determines change timing of downstream and upstream transmission clock rates, and change timing of upstream data for time-division multiplexing to instruct each of the optical network units. Both the optical line terminal and the optical network unit change the transmission clock rates with substantial synchronization therebetween.

Abstract: A system for serving N optical communication lines by a redundant set of modules in an optical network; where the set of modules comprises N>1 main modules and one backup module, N optical splitters, 2N fiber connections and a control means. In the system, each of the N optical splitters is connected to two different modules of the set by two respective fiber connections out of the 2N connections, while each of the N optical splitters is also coupled to one of the N optical communication lines. The arrangement is such that the control means selectively activates/inactivates any of the fiber connections for respectively enabling/blocking transfer of data there-along; the control means thus ensures that each specific line of the N optical communication lines is always served by either one or another of two different modules.

Abstract: Various methods and apparatuses are described for a wavelength division multiplexing passive optical network (WDM-PON) that performs bi-directional communication. The WDM-PON may include two or more remote distribution nodes in between a central office and the most distant optical network unit. Each remote distribution node is located in a physically separate location. A first remote distribution node has two or more optical network units connected to the first remote distribution node. Each remote node separates one or more wavelength channels from a composite optical signal distributed through that remote distribution node.

Abstract: The subject matter disclosed herein relates to synchronizing network timing. In one particular example, network timing may be synchronized using reflected signals.

Abstract: In a passive optical communication network system, an optical signal OCDM-coded is transmitted from an OLT to a first port of a circulator, which in turn transfers the signal from its second port to one end of a first SSFBG. The first SSFBG then decodes the signal of one channel to output the decoded signal from its one end to the second port of the circulator, which in turn transmits the decoded signal from its third port to an ONU. When the ONU transmits an optical signal to the third port of the circulator, the circulator transfers the signal from its fourth port to one end of a second SSFBG, which in turn encodes the signal to output the encoded signal from its one end to the fourth port of the circulator. The circulator then transmits the encoded signal from its first port to the OLT.

Abstract: When a neighbor ONU receives a signal with light intensity high enough to secure communication between an OLT and a remote ONU, the light intensity may be excessively high to damage a receiver of the neighbor ONU. In order to avoid such a problem, each ONU is notified of a downstream signal transmission plan (downstream light intensity map) prior to transmission of a downstream signal. Each ONU receives the downstream light intensity map (light intensity transmission schedule of downstream signal) in advance. Thus, the neighbor ONU can block or attenuate an optical signal addressed to the remote ONU, and the remote ONU can determine normal operation even when the remote ONU cannot receive a signal addressed to the neighbor ONU. Thus, the remote ONU can be prevented from issuing a wrong error signal.

Abstract: In a PON system in which communication is performed at a plurality of types of transmission rate (L, M, and H) in an upstream direction from a plurality of terminals connected to a station apparatus through optical fibers, within a discovery period for allowing an unregistered terminal to be recognized by station apparatus, the terminal makes a discovery response at one type of transmission rate (L). With this configuration, station apparatus can wait for a discovery response with a receive function being allowed to support transmission rate (L).

Abstract: Methods, systems, and computer-readable media provide for notifying an optical line termination (OLT) of a power failure. According to embodiments, a method for notifying an OLT of a power failure is provided. According to the method, a notification of a power failure at an optical network termination (ONT) is received. In response to receiving the notification, power is retrieved from a dedicated power storage unit dedicated to providing power for the transmission of a dying gasp alarm. The dying gasp alarm is transmitted to the OLT utilizing at least a portion of the power from the dedicated power storage unit. The dying gasp alarm notifies the OLT of the power failure.

Abstract: A system and communication method for the system interconnecting the optical network with the radio communication network is provided. The solution mainly applies to an optical access network employing fiber for transmission and the radio communication network connected to the optical access network, wherein a base station of the radio communication network is connected to the optical access network and communicates to an entity in the optical access network to achieve interconnection between the optical network and the radio communication network. After the interconnection is established, a user equipment can enjoy communication services through the interconnected radio communication network and the optical network.

Abstract: An optical line terminal calculates a requirement threshold for each optical subscriber unit based on a difference between the time average allocated bandwidth of each optical subscriber unit and the target bandwidth, and notifies a corresponding optical subscriber unit of the calculated requirement threshold. The corresponding optical subscriber unit then notifies, based on the data amount accumulated in a buffer, the optical line terminal of a data amount, as a transmission requirement, up to a data separation that is less or equal to the notified requirement threshold and in which a maximum transmission amount can be transmitted. The optical line terminal then notifies the corresponding optical subscriber unit of a transmission permission amount in which the data equal to the transmission requirement of which the optical line terminal is notified can be transmitted. The corresponding optical subscriber unit then transmits the data amount corresponding to the transmission permission amount.

Abstract: A passive optical network is disclosed that enables burst mode operation without some of the disadvantages for doing so in the prior art. An embodiment of the present invention comprises a receiver that receives optical signals from transmitters of a plurality of optical network units. For each transmission from an optical network unit, the receiver provides an output signal based on a comparison of the optical signal and a reference voltage that is specific to that optical network unit. A digital-to-analog converter generates the reference voltage in a data rate-independent manner based on information provided to it from the control plane.

Abstract: An optical transmission system is provided. The optical transmission system includes a user side optical repeater device, a central office side optical repeater device, and wavelength multiplexing and wavelength de-multiplexing functions. The user side optical repeater device is to be connected with a user side optical network unit, transmits data in two ways, and is used for wavelength division multiplexing. The central office side optical repeater device is to be connected with a central office side optical line terminal, transmits data in two ways, and is used for wavelength division multiplexing. The wavelength multiplexing and wavelength de-multiplexing functions are used for relaying between the user side optical repeater device and the central office side optical repeater device.

Abstract: When a frame is received from one of PON ports 12a to 12c of ONUs 1a to 1c, an OLT 3 compares VPIDs contained in Preamble/SFD regions A of the received Ethernet® frame with VPIDs assigned to LAN ports 31 and 32 of the OLT 3. Upon coincidence, a PON MAC process is started. When a frame is received from a PON port 33 of the OLT 3, each of the ONUs 1a to 1c compares a VPID contained in a Preamble/SFD region of the received Ethernet® frame with VPIDs assigned to the ONUs 1a to 1c. Upon coincidence, a PON MAC process is started.

Abstract: Embodiments of the present invention disclose a method for the generic mapping procedure GMP mapping, a method for GMP demapping, and an apparatus. The method for mapping includes: carrying, in an overhead GMP OH of the ith GMP block container, information about a TS that needs to be occupied by the (i+n)th GMP block container; adjusting the (i+n)th GMP block container according to the information about the TS that needs to be occupied by the (i+n)th GMP block container; performing, according to the adjusted (i+n)th GMP block container, the GMP mapping on customer service data to be sent, so that a receive end is capable of adopting a corresponding demapping manner according to a change of the block container, which implements lossless mapping and demapping processing by adopting a GMP for a variable block container.

Abstract: An optical communication system has a master station and a plurality of slave stations connected thereto via an optical fiber network, which is provided with an optical splitter and a relay unit which relays signals transmitted/received between the master station and the plurality of slave stations. The master station includes a first controller for performing ranging between the master station and the relay unit, and the relay unit includes a second controller for performing ranging between the relay unit and the plurality of slave stations. The master station determines, on the basis of the results of ranging performed by the first and second controllers as well as reports from the slave stations, timings for the slave stations to transmit signals to the master station, and receives signals multiplexed through the optical fiber network from the slave stations.

Abstract: The invention presents a method and a device for bidirectional IR data transfer between a medical treatment table, particularly an operating table (10a to 10d), and an operator control device (12a to 12d) which are subscribers in the IR data transfer and which each comprise an IR transmitter and an IR receiver, where the data to be transferred by a subscriber (10a to 10d, 12a to 12d) are split into data blocks which are transmitted in succession, with a respective break being observed between the transmission of the individual data blocks, and where data from another subscriber are transmitted within the breaks.

Abstract: An optical line terminal receives an optical signal transmitted by time division multiple access from plural optical network units among which are an optical network unit performing communications at a first bit rate and an optical network unit performing communications at a second bit rate. The optical line terminal includes a branching unit, a first receiving unit, and a second receiving unit. The branching unit branches the optical signal into branches, at an asymmetrical branching ratio. The first receiving unit receives a branch having the first bit rate, among the branches of a greater branched proportion. The second receiving unit receives a branch having the second bit rate, among the branches of a lesser branched proportion.