Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: A communications device 100, which performs data communication, includes an AC cycle sensor 30 which is connected to a power line 106 supplied with an a.c. voltage and generates a synchronous signal SS at timing of an a.c. voltage waveform AC of the power line 106; a data communicator 10 for performing data communication; and a communications controller 20 which performs communication of a control signal including information showing at least one of a communications device and a communications standard and controls the data communicator 101. When the a.c. voltage supplied to the power line 106 is an N-phase and when the cycle of the a.c. voltage waveform is T, data communication to be performed in a communication period subsequent to the period is controlled on the basis of the control signal included in the period of T/2M on condition that M is a natural multiple of N.

Abstract: An in-home-system master station of an in-home communication system detects a frequency band (a channel number corresponding to a data communication subchannel) or a time slot used by each station of an access communication system, using a coexistence signal subchannel. Based on the detected information, the in-home-system master station determines a frequency band or a time slot to be used in the in-home communication system to which the in-home-system master station belongs, so as not to avoid overlapping the frequency or time slot used in the access communication system, and informs each in-home-system slave station of the determined frequency band or time slot.

Abstract: An apparatus for causing a high-frequency signal to bypass a device that interrupts a communication over an electric wire, includes: four split cores that are arranged on four electric wires connected to the device, respectively; a first capacitor that is connected to a first electric wire and a second electric wire; a second capacitor that is connected to a third electric wire and a fourth electric wire; a first cable that connects the first split core and the third split core so that each of them functions as a transformer; and a second cable that connects the second split core and the fourth split core so that each of them functions as a transformer.

Abstract: An upper column address strobe signal and a lower column address strobe signal applied to a dynamic RAM are 180.degree. out of phase from each other. Data of n bits are read out from a memory cell array at a time. The data read out from memory cell array is divided into two bit groups and applied to an upper IO buffer and a lower IO buffer. Upper IO buffer and lower IO buffer latch sequentially the upper bit group and the lower bit group and output these groups to a data transmission bus in response to the upper column address strobe signal and the lower column address strobe signal.