Abstract: According to the data amount stored in a jitter buffer, which temporarily stores obtained data from a received voice packet, an operation timing of an output process of the jitter buffer and a data process of a codec and a modem is adjusted, the codec and the modem processing data that is sequentially output from the jitter buffer.

Abstract: A MODEM can shorten the processing time of an interface disposed between a data terminal equipment (DTE) and the MODEM. The MODEM stores an object program of a procedure in a memory and switches an operational mode of the MODEM automatically corresponding to the prescribed procedure thereby executing the procedure corresponding to the current operational mode. The MODEM further comprises a timer which monitors the transits time between a completed procedure and the next procedure, and the MODEM starts the process of a specified operational mode based on a mode-setting-instruction of the procedure as well as monitoring the transitions time by using the timer, and executing a next specified operational mode when the timer times out, thereby allowing the MODEM to perform the various operational mode switches.

Abstract: In an ATU-R having established a connection with an ATU-C and being in a state where data communication is enabled, the ATU-R being located at a user's home, a voltage detection circuit detects a connector voltage of a connector to which a network cable of a user side is connected. When the connector voltage is decreased below a predetermined value in a state where power is supplied to an ADSL circuit of the ATU-R, the power supply to the ADSL circuit is stopped while maintaining a function related to detecting the connector voltage and controlling the power supply. The connector voltage is monitored even after the power supply is stopped. When the detected connector voltage becomes greater than the predetermined value, the power supply to the ADSL circuit is resumed.

Abstract: After establishing a connection between an ATU-C and an ATU-R and having a state where data communication is enabled, the ATU-R checks a packet that flows through a network at the user side. When there is no packet addressed to the ATU-R for a predetermined time period, the ATU-R transmits, to the ATU-C, a request to transition to an energy-save mode. The ATU-C and AUT-R determines a parameter to be used for the energy save mode, the parameter enabling a number of carriers and/or transmission power to be decreased compared to the ones in a normal mode. Using the determined parameter, a state in which data communication is enabled is maintained.

Abstract: A processor executes an initialization sequence that exchanges predetermined signals prior to data communication. A complex operation circuit multiplies transmission data of a sub-carrier by gain compensation data and phase angle compensation data, which are prepared for the same sub-carrier. Therefore, modulation is done so that the multiplication results are simultaneously transmitted, by an IFFT unit, in a plurality of sub-carriers. In addition, the transmission data of a sub-carrier, during the data communication, is multiplied by gain compensation data and phase angle compensation data, which are prepared for the same sub-carrier.

Abstract: A DSL modem apparatus provided at a transmission side in an upstream performs upstream communication using carrier indexes of the same range as a downstream. During an echo canceller learning period, a transmission signal is outputted to a line, via notch filters that cut the signal at a frequency location of a PILOT signal of the downstream. An echo signal is received via notch filters and a coefficient is set by calculating from the training signal of its own apparatus and the echo signal.

Abstract: According to the data amount stored in a jitter buffer, which temporarily stores obtained data from a received voice packet, an operation timing of an output process of the jitter buffer and a data process of a codec and a modem is adjusted, the codec and the modem processing data that is sequentially output from the jitter buffer.

Abstract: The present invention provides a communication control method between DSL modem apparatuses mutually connected via a metallic cable. One of the DSL modem apparatuses transmits transmission data using a plurality of sub-carriers simultaneously, while the other DSL modem apparatus decodes the transmission data in the plurality of sub-carriers. The both sides of DSL modem apparatuses exchange data signals by mutually synchronizing and alternatively sharing transmission timeslots and reception timeslots, using the same range of sub-carriers. In addition, the upstream (data transmission from a remote side to a center side) uses the same range of carrier indexes that are used in the downstream (data transmission from the center side to the remote side).

Abstract: An ADSL modem apparatus is provided that accurately obtains a communication distance to an opposing ADSL modem apparatus, and that enables ADSL communication in an area exceeding the communication distance conventionally used. In the ADSL modem apparatus, a transmitter-receiver transmits and receives a carrier specified by a communication standard in a handshake procedure, and a processor estimates a communication distance to an opposing ADSL modem apparatus in accordance with a reception level of the carrier.

Abstract: A processor of a transceiver estimates a communication distance to an opposing ADSL modem apparatus by detecting a reception level of a REVERB signal in accordance with the ITU-T regulated G.992.1 or G. 992.2. Based on the estimated communication distance, and by referring to a table showing attenuation of signal energy (stored in a RAM), the signal energy in a high frequency band (among the signal energy assigned to transmitting signals) is concentrated into a low frequency band during the communication.

Abstract: A processor of a transceiver estimates a communication distance to an opposing ADSL modem apparatus by detecting a reception level of a communication distance detecting signal in accordance during an initialization sequence with the ITU-T regulated G.992. 1 or G. 992.2. The communication distance detecting signal is used to detect a communication distance to an opposing ADSL modem apparatus and has comb-shaped frequency characteristics. Based on the estimated communication distance, and by referring to a table showing attenuation of signal energy (stored in a RAM), the signal energy in a high frequency band (among the signal energy assigned to transmitting signals) is concentrated into a low frequency band during the communication.

Abstract: The data transmission apparatus comprises a memory to store control information of a modem at each destination address, and a communication control section for issuing a short procedure shift notification signal to execute the short communication procedure when the control information is stored at the memory, and issuing an ordinary communication initiation signal to execute the ordinary communication procedure when the control information is not stored at the memory.

Abstract: A modem parameter required for a modem apparatus is stored in a memory for each telephone number of a communication destination in advance based on past communications. At a communication time, a receiver side is notified of an execution of the short protocol by a QTSD signal, and sequentially a QINFO signal that includes the modem parameter is transmitted. Since the modem parameter is received by the communication destination, the pre-protocols such as exchange of parameter, etc., are shortened so that communication time can be shortened. Moreover, since the transmission of modem parameter is repeated until it is confirmed that the communication destination receives the modem parameter, occurrence of communication errors can be avoided so that the shortened pre-protocols can be surely executed.

Abstract: A MODEM can shorten the processing time of an interface disposed between a data terminal equipment (DTE) and the MODEM. The MODEM stores an object program of a procedure in a memory and switches an operational mode of the MODEM automatically corresponding to the prescribed procedure thereby executing the procedure corresponding to the current operational mode. The MODEM further comprises a timer which monitors the transits time between a completed procedure and the next procedure, and the MODEM starts the process of a specified operational mode based on a mode-setting-instruction of the procedure as well as monitoring the transitions time by using the timer, and executing a next specified operational mode when the timer times out, thereby allowing the MODEM to perform the various operational mode switches.

Abstract: A MODEM can shorten the processing time of an interface disposed between a data terminal equipment (DTE) and the MODEM. The MODEM stores an object program of a procedure in a memory and switches an operational mode of the MODEM automatically corresponding to the prescribed procedure thereby executing the procedure corresponding to the current operational mode. The MODEM further comprises a timer which monitors the transits time between a completed procedure and the next procedure, and the MODEM starts the process of a specified operational mode based on a mode-setting-instruction of the procedure as well as monitoring the transitions time by using the timer, and executing a next specified operational mode when the timer times out, thereby allowing the MODEM to perform the various operational mode switches.

Abstract: A digital signal detection circuit includes a threshold value calculator calculating a threshold value from assumptive sampled values corresponding to various data patterns of a regenerated signal. The regenerated signal is obtained by regenerating data recorded on a recording medium by a regenerating head. The detection circuit also includes a Viterbi decoder carrying out Viterbi decoding of the regenerated signal with the threshold value determined by the threshold value calculator as a constant. The threshold value calculator variably controls the threshold value using a decoded output of the Viterbi decoder and a regenerated signal corresponding to the decoded output of the Viterbi decoder.

Abstract: A method of counting the number of tracks on an optical disk each track comprising a plurality of sectors each having an address segment and a plurality of data segments, each of the segments having at its head portion a region for recording an access code representing a track number to which the segment belongs. The method comprises the steps of sampling the access code number through an optical head, obtaining a code number difference (V0) between the present sampled access code number (GC) and the previous sampled access code number (GC1), and adding the code number difference to a track count value (TCNT) to obtain the number of the tracks that the optical head moves to traverse. This method can accurately and surely count the number of the tracks of an optical disk.