Abstract: The present invention relates to a control apparatus for managing communications between a plurality of electric appliances connected to a household power line network. The apparatus transmits a plurality of types of modulation method control signals to each of the plurality of electric appliances, each type of control signal utilizing a different modulation method. When receiving a response from each electric appliance, the apparatus detects to which type of modulation method control signal the response was made and judges the type of the modulation method that is utilized in each electric appliance based on the detection.

Abstract: A communication control apparatus of the present invention detects a procedure signal transmitted from a calling side from signals received in reception section while or after a transmission section, which transmits procedure signals specified in the predetermined Recommendation, transmits a DIS signal specified in Recommendation T.30 or a procedure signal used in a data communication. Then, the apparatus shifts to a communication operation conforming to Recommendation V.8 when the detected procedure signal is a CM signal specified in Recommendation V.8, while shifting to a data communication operation when the detected signal is the procedure signal used in the data communication. Thus, the present invention enables the apparatus to shift to the communication operation corresponding to the detected procedure signal, and therefore it is possible to assuredly prevent the apparatus from causing the looped condition thereof.

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: 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: 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: The present invention relates to a control apparatus for managing communications between a plurality of electric appliances connected to a household power line network. The apparatus transmits a plurality of types of modulation method control signals to each of the plurality of electric appliances, each type of control signal utilizing a different modulation method. When receiving a response from each electric appliance, the apparatus detects to which type of modulation method control signal the response was made and judges the type of the modulation method that is utilized in each electric appliance based on the detection.

Abstract: A security system that protects an apparatus from (e.g. theft) comprises at least one secured apparatus having an identification code, an operation center having a memory with the identification code of the secured apparatus stored in association with an operation-permitting code and a gateway apparatus connecting the secured apparatus and the operation center. The gateway apparatus and the operation center are connected via a permanently connectable line, which is not subject to connection time charges. When the secured apparatus is turned on, the secured apparatus transmits the identification code to the operation center via the line. Then, the operation center searches the table for an operation-permitting code corresponding to the identification code, and transmits the operation-permitting code retrieved from the memory to the secured apparatus via the line, if the operation-permitting code corresponding to the identification code is found.

Abstract: In the present invention, when a procedure signal specified in a predetermined Recommendation is received from an answering side, a variable signal detection section detects signal components each at one of a plurality of frequencies from the procedure signal. Based on the detected result in the variable signal detection section, a comparison section outputs an identification signal indicative of a type of Recommendation. Based on the identification signal, a control section of a host controls the switching of operation modes of a modem.