Rohm Co., Ltd.

Mitsuhiko Noda

Shozo Miyagawa

Yoshihiro Ikefuji

Takashi Naiki

The sensor node communication terminal includes: a sensor capable of collect sensor information at an installed location in autonomous timing; a control unit connected to the sensor and capable of executing calculation processing of the sensor information; a memory connected to the control unit; a wireless transmission/reception unit connected to the control unit; an antenna connected to the wireless transmission/reception unit and capable of wirelessly transmitting the sensor information or a result of the calculation processing of the sensor information; a power supply unit connected to the control unit; and a timer connected to the control unit, wherein second wireless transmission data can be received from a host side during only a predetermined time period after transmission of wireless transmission data is completed. Moreover, there is provided a wireless sensor network system to which a plurality of such sensor node communication terminals can be applied.

Communication terminal and wireless sensor network system

A mobile communications system includes a base station that allocates a plurality of pairs of transmission and reception slots to one data frame and a portable terminal that communicates with the base station. At least two pairs of slots are allocated to one portable terminal so that one pair is used to continue a communication session and the other is used to control channels in order to secure a channel for the communication session. The portable terminal detects whether the communication condition is poorer than a first level and whether it is poorer than a second level that is lower than the first level. During a communication session, when the communication condition drops below the first level, the portable terminal requests another base station to newly establish a traffic channel, and, when the communication condition drops below the second level, it switches from the currently used traffic channel to the newly established traffic channel.

Mobile communications system with portable terminal for facilitating channel switching

Operation delay time of a demodulator is counted and outputted as a count value by a counting circuit. The count value is compared by a comparator with an output value of a counter which starts counting by being triggered by a synchronizing signal outputted by a timing generating circuit. The timing of the processing is delayed by a time corresponding to the operation delay time by a delay circuit provided in a codec circuit. Substantially the same processing is performed on the transmitting side.

Communication apparatus

A DTMF signal receiving circuit which is capable of freely selecting a frequency of a received dial tone signal. The DTMF signal receiving circuit receives a DTMF signal, decodes the DTMF signal, and outputs the signal as the decoding result. The DTMF signal receiving circuit comprises a dial tone signal detecting circuit for freely selecting a frequency of a dial tone signal which is the object of detection in accordance with a supplied selection signal, and a judging circuit for judging whether or not the signal as the result of detection of the DTMF signal is output on the basis of the output of the dial tone signal detecting circuit.

DTMF signal receiving circuit

Disclosed is a cross point mixer including a cross point switch and a mixing circuit provided on the output side. The cross point switch includes n.times.m switches arranged in a matrix manner. Each of the switches corresponds to one of a plurality of n input terminals receiving signals, and corresponds to one of a plurality of m output terminals outputting signals. When on, each of the switches forms a signal transmission path which connects a corresponding input terminal with a corresponding output terminal. The mixing circuit provided on the output side receives signals from the n switches correspondingly associated with the output terminal, and subjects the signals to mixing for output to the output terminal.

Cross point mixer for a telephone set

A directory answering machine which allows a desired telephone number which is registered in the form of an abbreviated dialing code to be found by an access from an external telephone even when the abbreviated code is forgotten. When a predetermined remote command is received from an external telephone to the answering machine through the telephone line, a control circuit serially reads out the telephone numbers registered in an abbreviated dialing code information memory in the form of abbreviated dialing codes and the subscriber names thereof, converts the read data into speech synthesized by a voice synthesizer, and supplies them to the telephone line through a communication circuit. When a predetermined selection signal is supplied from the external telephone, the subscriber name and the corresponding telephone number which are being output at this point in time are selected. The data are supplied again to the telephone line in a synthesized speech. The resupply may be repeated in response to a repeat signal. In this way, a desired telephone number can be found out from the external telephone.

Directory answering machine

A cross point switch mounted on a telephone-related device such as a telephone. When an alternate power source request signal is low, switches are controlled in response to external data. When the signal is high, a predetermined switch or switches are forced to be turned on and other switches are forced to be turned off. As a supply voltage obtained from a commercial power supply drops, the request signal goes high. When the request signal is high, a voltage obtained from telephone line power is supplied only to necessary electric circuits. Only the most basic functions such as talking over a telephone line can be used such that power consumption can be minimized.

Cross point switch with power failure mode

A data backup apparatus for temporarily storing the data stored in a volatile memory using an internal battery when the main power is stopped. When the operation of the internal battery is started, the data stored in the volatile memory as a digital signal is converted into an analog signal by a D/A converter, and then it is stored in a magnetic storage unit. When the power supply is restored, the data stored in the magnetic storage unit as the analog signal is read out and converted into the digital signal, and then it is restored to the volatile memory.

Telephone power interruption data backup apparatus

A side tone preventive circuit for telephones which prevents the output of the transmitter on the speaker's side from being transmitted to the receiver on the same side. The balance of the impedance bridge in a bridge circuit for separating a transmission signal and a reception signal is automatically adjusted in accordance with the circuit impedance at the location at which a telephone is installed. An impedance measuring circuit measures the impedance of the telephone circuit, and a balance adjustment circuit the impedance of which is adjustable is provided in the bridge circuit. The impedance of the telephone circuit is measured at the time of installation of a telephone, and the impedance of the balance adjustment circuit is adjusted in correspondence with the result of measurement. Thus, the impedance balance of the bridge circuit is adjusted in correspondence with the circuit impedance, thereby effectively preventing a side tone.

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Kyoto, Japan

Mitsuhiko Noda