Abstract: A time domain duplex cable system includes a mechanism to change the communication direction of spectrum used in a cable plant including a Cable Modem Termination System (CMTS), a Fiber Node and a plurality of cable modems in communication with the CMTS via the Fiber Node. Active devices, e.g., directional amplifiers switch the communication direction of the cable plant in response to timing information received from the CMTS. To avoid collisions of downstream and upstream packets, a guard time is determined and used in connection with generating the timing information. In one embodiment, the timing information is transmitted in one or more Data Over Cable Service Interface Specifications (DOCSIS) Media Access Protocol (MAP) messages transmitted by the CMTS towards the cable modems.

Abstract: Provided are methods and systems of using division-free duplexing (DFD) in a cable communication network. Techniques for applying DFD in a cable communication network may enable data to be transmitted and received over a coaxial cable without using division duplexing techniques. For example, the cable communication network may include DFD enabled network nodes and each subscriber to the cable network may be equipped with a DFD system configured to operate in a DFD mode. In some embodiments, oppositely propagating signals may be transmitted over one frequency channel, and DFD techniques may be used to recover originally transmitted signals. Further, in some embodiments, DFD techniques may be used with encryption methods to increase the security of data transmitted in the cable communication network.

Abstract: A method and a circuit for controlling a reception path of a multi-standby terminal are provided. If a first communication module is in a transmission state, all filters disposed in a reception path of a second communication module are activated. If the first communication module is not in a transmission state, fewer than all of the filters disposed in the reception path of the second communication module are activated. A plurality of filters disposed in the reception path of the second communication module are activated partially or fully according to the transmission state of the first communication module.

Abstract: A device and method of duplex audio communication over a broadcast channel are disclosed. Low-power transmission over a broadcast channel is permissible for personal use as long as the transmitted power level is below a level allowed by respective regulatory. For example, low-power FM transmitter can be used to provide a wireless audio link between two audio devices. One such application scenario is a wireless speakerphone used as an audio extension from a cellphone for group conference purposes. Such applications face issues of potential interference from other users of the same channel and the need of manually selecting and tuning a pair of channels. The device and method disclosed in the present invention use the clear channel technique to automatically select an un-occupied channel for the transmit side and utilizes an identification embedded in a sub-channel to allow the receiver to automatically tune to the channel used by the transmitter.

Abstract: A filtering device comprises an analogue quadrature splitter together with a first filtering element and a second filtering element. The filtering device is adapted to transform filtering characteristics of the first filtering element and filtering characteristics of the second filtering element into an effective filtering characteristic present in an output signal at an output terminal of the analogue quadrature splitter. The first filtering element and the second filtering element comprise filtering elements of high accuracy, with a steep roll-off but poor power handling capabilities. Using a high power quadrature splitter it is possible to transform the filtering characteristics of the first filtering element and/or the second filtering characteristic of the second filtering element into the effective filtering characteristics.

Abstract: Embodiments of a method and apparatus for generating an estimated non-linear echo signal are disclosed. One method includes receiving a plurality of data inputs. The plurality of data inputs are partitioned into subsets. A weight vector is computed for each of the subsets. A vector of addresses to memory locations is computed for each of the subsets. Values of interpolants are accessed at the memory locations (interpolation sites) based on the vector of addresses for each of the subsets. The estimated non-linear echo signal based is calculated on the values of the interpolants and the weight vector corresponding to each subset.

Abstract: A signal communication apparatus comprising first and second channels for communicating signals between two electronic devices; each of said first and second channels has a transmitter for transmitting signals, a receiver for receiving signals and an interface arranged between the transmitter and the receiver. The transmitters code the signals in the form of a frame of H bits, with H being an integer, and adapted to serially transmit said frame of H bits through said interface, and the receivers decode the frames of H bits, a frame of H bits having P data bits, K redundancy bits and a sequence of L control bits adapted to identify the type of frame to be transmitted, with L, P and K being integers.

Abstract: A computer can control a target device using a packet format described herein. In one example, an extension packet controls the target device in at least one of power consumption, image rendering, and register updating.

Abstract: Method for transmitting through a bidirectional communication channel at least one conventional frame (CVFR) split into time slots SLI (for j=1 to L) separated from each other by guard intervals G, each time slot SLI being allocated either to a first or to a second direction of communication uplink (UL) or downlink (DL) offered by the bidirectional communication channel. The method according to the invention includes: detecting at least two successive time slots SLj, SLm+1, SLj+2 allocated to a same direction of communication DL, and inserting data in the guard interval separating such successive time slots SLj, SLj+1, SLj+2.

Abstract: Methods and systems for supplying data objects to users of a communication system are disclosed. In an exemplary method a session is established between a first and second communication device, and a primary data object providing first information pertaining to a user of the first communication device is transferred to the second communication device upon the occurrence of a triggering event at the first communication device. A request for a secondary data object is transferred from the second communication device to a data server, the request including the first information and further including information pertaining to the user of the second communication device. A secondary data object intended for rendering at the first and second communication devices is created and transferred to the first and second communication devices.

Abstract: A transceiver, receiver, and transmitter are provided. The transmitter includes an in-phase path for an in-phase signal, a quadrature path for a quadrature signal, a first path associated with a first local frequency, a second path associated with a second local frequency, and a band selector for swapping the in-phase and quadrature paths with respect to the first and second paths so that one of the in-phase and quadrature paths communicates with the first path and the other communicates with the second path. The receiver includes an in-phase path, a quadrature path, a polyphase filter having first and second inputs and first and second outputs, and a selector for swapping the in-phase and quadrature receive paths to switch connection between the in-phase and quadrature receive paths and the first and second inputs. The transceiver may include the receiver and the transmitter.

Abstract: A communication apparatus which may include a power supply that acquires a supply voltage from a power line connected from outside, a transmission control unit that transmits a pilot signal and signals subsequent to the pilot signal to the power line, a pilot signal detection unit that detects pilot signals transmitted to the power line by other apparatuses, and a timing adjustment unit that adjusts transmission timing of the pilot signal of the communication apparatus in accordance with that of the pilot signals transmitted by the other apparatuses.

Abstract: The present invention provides a communications system, presence server, and communications method used for them, which determines an optimum operation for phone call taken into account presence information of caller. The presence server compares a priority level allocated to caller presence information with a priority level allocated to receiver presence information, selects optimum operation from preset operations based on the comparison result and controls a exchange according to the selected operation.

Abstract: The present invention allows a mobile terminal to automatically log on to an access network, and potentially log on to an entity on the access network or associated network based on the communication zone from which communications are afforded. The mobile terminal can detect one or more available access points associated with one or more communication zones and determine the most appropriate communication zone to use when obtaining network access. Based on the selected communication zone, the mobile terminal will obtain logon information from a logon profile. The logon information will provide sufficient information to allow the mobile terminal to obtain network access via the appropriate access point. Additional logon information may be provided for logging on to a network entity once network access is afforded.

Abstract: The present invention relates to a method of transmitting and receiving data in soft handoff of a wireless communication system. According to an aspect of the present invention, in the method of receiving data in soft handoff of a wireless communication system, a mobile station receives a first sequence being generated by interleaving transmission data using a first interleaver pattern, and also receives a second sequence being generated by interleaving the transmission data using a second interleaver pattern. Then, the mobile station combines and decodes the first sequence and the second sequence before receiving an entire frame having the first sequence allocated thereto.

Abstract: A system for full duplex communication using a single-ended communications link is described. The system includes a first link interface configured to generate a signal for transmission via the single-ended communications link. The signal includes data encoded in a forward channel. The system also includes a second link interface configured to receive the signal from the first link interface via the single-ended communications link and modulate the signal to encode data in a reverse channel so that the signal includes the forward channel data and the reverse channel data simultaneously.

Abstract: Systems and methodologies are described that facilitate reliably receiving a sequence of data packets in a wireless communications environment. In particular, mechanisms are provided that enhance hybrid automatic repeat request protocols through validation of acknowledgment message detection by re-decoding. A transmitter sends a data packet from a sequence of packets in one or more data transmissions. A receiver acknowledges the data packet upon obtaining sufficient transmissions to decode the packet. The receiver re-decodes a successive data transmission in combination with previously received transmissions to validate if the transmitter detected the acknowledgment.

Abstract: The present disclosure provides a duplexer for separating a transmit signal and a receive signal. The duplexer comprises a transmit filter, a receive filter and an analogue quadrature splitter, a first filtering element and a second filtering element. By choosing the first filtering element and the second filtering element substantially identical, it is possible to transform filtering characteristics of the first and second filtering element such that stop bands are substantially transformed into an effective pass band, and vice versa. The analogue quadrature splitter is adapted to increase an attenuation of the transmit signals outside the transmit band, such as in the receive band. Therefore out-of-band emissions by the transmitter will be substantially reduced. The present disclosure further provides a method for separating a transmit signal and a receive signal, and computer program products for the manufacture for carrying out the method of separating transmit signals and receive signals.

Abstract: An improved method and a communication means node implementing the method for load control in connection with a multimedia service transmission intended for multiple receivers over a wireless network are disclosed. The receivers in the wireless network are able to respond to requests communicated from an ordering entity by feeding back responses to a management entity in said wireless network. The feedback of these responses uses a different communication means, separate from said wireless network. This different communication means has limited communication resources. A transmission load caused in said different communication means by said feedback of said responses is according to the invention controlled by the different communication means itself.

Abstract: In one embodiment a method is provided for requesting and receiving network statistics in-band of a data replication exchange. The method includes receiving, at a switch, a request packet, initiated from a data replication system, for in-band delivery of network statistics, modifying the request packet to include a command that can be processed by a data storage device that is periodically accessed in connection with the data replication system, sending the request packet including the command to the data storage device, receiving from the peripheral device, in response to the request packet including the command, a response packet that includes data responsive to the command, deleting from a data field of the response packet the data responsive to the command and adding to the data field network statistics data available to the switch, and sending the response packet including the network statistics data to one of another switch or a host device from which the request packet was sent.

Abstract: Methods, parallel computers, and computer program products are disclosed for remote direct memory access.

Abstract: Provided are a method and apparatus for transceiving an asymmetric point-to-point moving signal and securing an uplink channel using a horizontal blanking interval (HBI) in which a video signal transceiving apparatus can combine a plurality of HBIs and a plurality of active lines (ALs) into a single section, and when auxiliary data exists in a corresponding HBI, can change an order of the HBI to the last and transmit map information including arrangement information to a video signal display apparatus, and the video signal display apparatus can receive the map information and analyze the received map information to thereby acquire an uplink channel using HBI excluding auxiliary data and transmit control signal data via the acquired uplink channel.

Abstract: A communications system and method of transferring data over the communications system. The system includes audio communications devices (telephones and/or, soft phones) connected to Session Initiation Protocol (SIP) endpoints with multiple line capabilities and a unique Uniform Resource Identifier (URI) associated with audio communications that has the form x@y.z. A file transfer agent system running a File Transfer Application Agent (FTAA) application is also connected at each of SIP endpoints, and has a unique URI that has the form ft.x@y.z. Parties conducting a phone conversation at SIP endpoints can initiate file transfers between the file transfer agent system from respective audio communications devices without otherwise accessing the file transfer agent system.

Abstract: A portable device, such as a mobile terminal or user equipment, for encoding uplink acknowledgments to downlink transmissions. The portable device includes a receiver configured to receive a plurality of data blocks, such that each of the data blocks include an associated cyclic redundancy check (CRC), and a processor configured to determine received status for each of the data blocks by checking the CRC of each of the data blocks. The portable device further includes a transmitter for transmitting a response sequence which indicates the received status of all of the data blocks.

Abstract: In a communication apparatus capable of switching states in response to a request from an external device, the communication apparatus switches states between said second state where the communication apparatus replies a valid response under limited circumstance and the third state where the communication apparatus does not reply a valid response before a registration; and said first state where the communication apparatus replies a valid response and said third state after the registration based on the same setting.

Abstract: A mobile communication method according to the present invention includes performing, at a mobile station UE which establishes a first connection in a first cell, a cell selection process at the time of detecting a failure in the first connection and transmitting, from the mobile station UE to a second cell selected in the cell selection process, a connection re-establishment request signal. The method includes determining, at a radio base station that manages the second cell, whether or not to store context information of the mobile station UE in response to the connection re-establishment request signal and acquiring, at the radio base station, the context information of the mobile station UE from a radio base station that manages the first cell, and establishing a second connection in the second cell for the mobile station UE, based on the context information of the mobile station UE.

Abstract: A wireless communication system which includes a transmitter and receiver each having two or more antennae, the system including: a channel condition determining unit which determines a condition of a channel between the transmitter and the receiver; and a system control unit which changes a transmitting system in the transmitter and a receiving system in the receiver in accordance with a determination result obtained by the channel condition determining unit.

Abstract: An implementing method for removing duplication protection for multimedia messaging service interworking forwarding message and multimedia messaging service interworking gateway. The method determines whether to return response message according to the different value of the acknowledgement request field of the request signaling. Using the SMTP-interactive-status code as a criterion, when the acknowledgement request field is set to be “NO”, requesting not to return the response message, and when the acknowledgement request field is set to be “YES”, requesting to return the response message. Determine whether the forwarding is successful by determining whether the SMTP-sending-status code returned by the response signaling is received according to the replying status of the response signaling.

Abstract: An irrigation system includes an irrigation controller, at least one environmental sensor and a vandal resistant data relay. The irrigation controller includes a two conductor hard wired communications link for accepting an actual value of at least one parameter of interest from an environmental sensor in the form of data encoded on the conductors via current modulation. The environmental sensor is mounted in a location remote from the irrigation controller. A circuit is connected to the environmental sensor for transmitting an RF signal representing an actual value of a parameter of interest detected by the environmental sensor. The vandal resistant data relay is connected to the two conductor hard wired communication link of the irrigation controller.

Abstract: A network device for establishing quality of service (QoS) between two terminal devices includes a transceiver module and a state-machine setting module. The transceiver module is configured for receiving establishing requests, request responses, acknowledge messages, and QoS requests from any one of the two terminal devices. The state-machine setting module is configured for setting a state of the network device according to a current state of the network device and messages received by the transceiver module, and the state of the network device includes an idle state, an inviting state, a trying state, an acknowledge state, and a QoS state.

Abstract: A system for arbitrating a transmission of data includes a number K of transmitters, a request signal transmission device, a device valid signal transmission device, and a data valid logic device, wherein a transmitter asserts a request signal to request permission to begin a data transmission and transmits transmission-identifying information to a receiver. The data valid logic device deasserts a data valid signal based on the state of a wait signal, thereby preventing a transmission of data from each of the K transmitters at one clock cycle after a clock cycle at which the data signal is deasserted. An arbitration logic device of the receiver selects one of the number K of transmitters to grant permission to transmit data to the receiver and outputs an arbitration signal to a wait logic device instructing the wait logic device to deassert the wait signal of the selected trnasmitter.

Abstract: The present disclosure teaches a filtering device. The filtering device comprises a transforming unit, at least a first filtering element and a complementary filtering unit. The filtering device of the present disclosure allows an isolation of radio signals within a selected frequency band. Frequency bands closely-spaced to the selected frequency band may be suppressed. The present disclosure provides a reliable and almost identical response to temperature changes for the pass band within the selected frequency band and the stop bands closely-spaced to the selected frequency band. The filtering device withstands temperature changes without affecting a filtering performance different to the prior art. The present disclosure further provides a method for filtering an input signal as well as a computer program product for the manufacture of the filtering device and a computer program product for the carrying out of the method of filtering.

Abstract: A data transmission/reception method in Near Field Communications (NFC) for improving data throughput is provided. Communications between a first NFC device and a second NFC device which perform NFC includes (a) transmitting, by the first NFC device, a data frame to the second NFC device, (b) setting, by the second NFC device, an indication of presence or absence of more-data in a bit of a Logical Link Control (LLC) information frame and transmitting the LLC information frame as a response frame responding to the data frame transmitted from the first NFC device, and (c) checking, by the first NFC device, the bit of the response frame and waiting for predetermined time or immediately transmitting a next transmission data bit without waiting for the predetermined time according to the check result.

Abstract: An oscillation-echo preventing circuit has a microphone/speaker unit and a voltage-canceling circuit for canceling voltages of audio receive signals. The microphone/speaker unit has a main body, at least two microphones, and a speaker or an earphone. The microphone seals a first inside space from an outside space. The microphone seals the first inside space from a second inside space. The speaker or the earphone seals the first inside space from the outside space. The voltage-canceling circuit cancels out the voltages of audio receive signals coming from the microphones, respectively, generating an output of minimum magnitude. Thus, the circuit can sufficiently suppress oscillation and echoing.

Abstract: A wireless communication device, and a wireless communication system and a method of beamforming is presented. The wireless communication system and/or device includes a beamformee unit, a beamformer unit and two or more antennas to transmit the data unit and the protocol data unit according to the beamformee and the beamformer units, respectively. The beamformee conveys feedback information by a data unit in one of the feedback positions that include an immediate feedback position, an aggregated feedback position and a delayed feedback position. The beamformer unit generates a protocol data unit including a control field that includes one of the feedback request information types which is selected from a Channel State Information or uncompressed Steering Matrix or compressed Steering Matrix to request feedback from a remote communication device.

Abstract: An aircraft communication system includes an aircraft component, an Integrated Modular Avionics (IMA) unit, an Onboard Maintenance System (OMS), and a switch. The switch routes data provided by the aircraft component via a first communications protocol to the IMA unit, and mirrors the routed data to the OMS via a second communications protocol. The OMS processes and stores the received data, part of the received data, or the results of said processing.

Abstract: There is provided a radio measurement procedure for station statistics measurements in wireless communication network. In the method, the requesting station transmits to a requested station a request message for triggered RSNA station statistics measurements including a group identity field which indicates the requested RSNA statistics group and a triggered reporting field for RSNA counters which is used to specify trigger conditions comprising reporting triggers and RSNA statistics thresholds for the corresponding reporting triggers. And, the requesting station receives from the requested station a RSNA statistics measurements report message including measured RSNA statistics for the reporting triggers specified in the triggered reporting field for the RSNA counters when the measured RSNA statistics exceeds the corresponding RSNA statistics thresholds specified in the triggered reporting field for the RSNA counters.

Abstract: The IC card is mounted on the read and write device and the first electrostatic induction electrode and second electrostatic induction electrode are formed facing each other. The data signal is outputted from the first transmission and reception circuit to the first electrostatic induction electrode when the data signal is transmitted from the IC card to the read and write device. Then the first electrostatic induction electrode is charged based on the data signal and the electrostatic induction signal of the opposite polarity is induced at the second electrostatic induction electrode. The inverted data signal appears at the second electrostatic induction electrode. The second transmission and reception circuit of the read and write device receives and amplifies the inverted data signal, leading to the non-contact data communication with lower energy consumption and the lower cost.

Abstract: In a mobile communication method according to the present invention includes the steps of: transmitting, from a handover source radio base station to a switching center, a handover request including an Next hop Chaining Count (NCC), a Physical Cell Identification information (PCI) and a KeNB*; changing, at the switching center, the NCC, changing, at the switching center, the KeNB* on the basis of the PCI, and transmitting, from the switching center to the handover target radio base station, the handover request including the changed NCC and the changed KeNB*; generating, at the handover target radio base station, a first key on the basis of the KeNB*; and generating, at the mobile station, the first key on the basis of the NCC and the PCI included in a handover command.

Abstract: Described herein are a number of steps, methods and/or solutions that can be applied to greatly improve attenuation control of RF signals in cable plant. The present disclosure is directed to a cable modem auto-attenuation system or any other signal transferring system. The system may be capable of taking a high-power signal from the cable plant's service line, dropping the power value down to a usable level and transmitting the signal to a cable modem while eliminating the need for rigorous manual adjustments that a normal cable modem often requires. In certain embodiments, the system may be integrated into a separate device connected between the modem and the cable company service line and configured to handle upstream and downstream attenuation separately or jointly.

Abstract: A second output transmission signal (“TX2”) added to a line driver is a scaled version of the main output transmission signal (“TX1”). TX2 is scaled from TX1 by a variable scale factor K. An adaptive hybrid circuit subtracts TX1 and TX2 from a line signal carrying both a line transmission signal and a line received signal (“RX”). A programmable impedance Ztune is coupled between the TX2 output of the line driver and the RX output of the adaptive hybrid circuit. A transmission echo in the output RX signal is measured. K and Ztune are then adaptively tuned to minimize the transmission echo. The hybrid in this case becomes a 4-port network, one port specifically added to adaptively cancel the transmission echo in the RX output of the adaptive hybrid circuit. Alternatively, the hybrid may be a 3-port hybrid including variable impedances to cancel the line transmission signal.

Abstract: A method and apparatus for transmitting and receiving packet data between a UE and an Enhanced Node B (ENB) using a Hybrid Auto Repeat Request (HARQ) scheme in a mobile communication system. The method includes the steps of receiving configuration information from an ENB, the configuration information including a first Maximum Retransmission Limit (MRL) value to be applied to data that is transmitted over a persistent resource, and when data to be transmitted by the UE is quasi-real time data, transmitting a first data packet to the ENB by using the persistent resource and applying the first MRL value the first data packet, which is configured from the quasi-real time data.

Abstract: A transmission protocol is provided for wireless communications in an OFDMA system that uses a rateless code and techniques are provided for dynamically adjusting the subcarrier resources allocated to an OFDMA relay node so that the relay is used at the right time according to the instantaneous channel state information (CSI). As a result, a higher throughput is achieved between source and destination nodes based on a low complexity algorithm for determining when relay assistance is helpful for completing a transmission between the source and destination nodes.

Abstract: An RFID communication system comprises an NFC device (11) and a smart card (2) with contactless card functionality, wherein the NFC device (11) and the smart card (2) are couplable to each other via a protocol converter (7), wherein the NFC device (11) is coupled to an antenna (3) to receive electromagnetic signals (ES) from an RFID reader/writer and to transmit response signals (RS) to the RFID reader/writer by modulating received electromagnetic signals (ES). The electromagnetic signals (ES) contain first and second characteristic components (FE, RE) which define the begin and the end of a predefined signal pattern (PA), wherein the second characteristic component triggers a predefined response delay time (FDT) at the expiration of which the RFID communication system has to respond to the RFID reader/writer. A device (12) for compensating signal delays is provided that comprises signal pattern shortening means (13).

Abstract: In one embodiment, a method for monitoring traffic associated with users in a network includes assigning a trust level to each of the users, monitoring traffic associated with each of the users, and analyzing the monitored traffic. A level of monitoring is based on the trust level of the user. A user's trust level is modified if the analyzed traffic indicates that the user is operating outside of specified network usage parameters. An apparatus for monitoring traffic associated with users in a network is also disclosed.

Abstract: A method for generating a codebook to encode embedded information is described. A distribution pattern of symbols is determined. A first number of codewords associated with the distribution pattern of symbols is determined. A subset of codewords from the first number of codewords is selected. The subset of codewords is included in the codebook if the subset of codewords satisfies predetermined performance criteria.

Abstract: A network node (1) with a communication unit (2), which is provided for the implementation of a communication protocol for the purpose of communication with other network nodes via a communication medium (5), and with a bus monitor (3), which, mutually independently, each implement an access time schedule contained in a configuration data record, and which each make available, in accordance with the access time schedule, a release signal for a bus driver (4) provided in the network node (1), which evaluates these two signals and, in the event that the two release signals do not coincide, blocks the access of the network node (1) to the communication medium (5).

Abstract: A dual mode communication device utilizes a control channel to exploit diversity, history, and context in advance of establishing a broadband data exchange session on a broadband but shorter range wireless data channel, maximizing productive use of such a session. Appropriate diversity for the negotiated session further enhance data transfer, including path diversity, radio technology diversity (e.g., WiMax, Wi-Fi, ultra wideband, Bluetooth), antenna diversity (e.g., MIMO), modulation diversity (e.g., rate selection for 802.11, or symbol length selection to combat multi-path fading), and frequency diversity (e.g., 2.4 GHz versus 5 GHz). Historical information about channel characteristics optimize the selection of channel parameters with respect to the diversity choices. In addition, context information such as location and speed can be used to categorize the historical information that is collected to further optimize channel parameters.

Abstract: A large amount of user information is transmitted with good efficiency by means of a high-speed downlink by making transmission rates of an uplink circuit and a downlink asymmetrical. The radio communication system includes a plurality of base stations, a plurality of terminals, an uplink established between each of the base stations and each of the terminals for the purpose of radio transmission of prescribed information from a terminal to a base station, and a downlink circuit established between each of the terminals and each of the base station for the purpose of radio transmission of prescribed data from a base station to a terminal.

Abstract: An object of the invention is to arrange so that the digital signal transmission between specific equipments connected with each other by the transmission line of a fixed standard can be performed securely and satisfactorily. When a digital signal destination is caused to receive a fixed digital signal sent out of a digital signal sender, the digital signal destination acquires at the request of the destination from the digital signal sender data on modes in which the digital signal sender is able to send out the digital signal, and a transmission mode of the digital signal is caused to be set by a command based on the acquired mode data from the digital signal destination. Moreover, when a digital signal destination is caused to receive a fixed digital signal sent out of a digital signal sender, a flag is added to the digital signal sent out of the digital signal sender, which indicates that the transmission rate is being adjusted based on the command from the digital signal destination.