Tamura Electric Works, Ltd.

Ddk Ltd.

Yoshiaki Takeda

Osamu Kai

Hiroyuki Asano

Takashi Oyamada

Tomonari Otsuki

Jinichi Mashiyama

Toshiharu Kinoshita

Toshiaki Hayasaka

Shigehiro Eda

Kazuo Asada

Toshimichi Kubota

A C-shaped compliant contact is composed of a connection portion to be connected to an electric cable or the like, a press-fitting portion to be press-fitted in a through-hole of the printed circuit board, and a contact portion to contact a contact of a mating connector. The press-fitting portion has an inner periphery forming a U-shaped groove in section and an outer periphery forming at least one arc portion. The circle inscribing the inner periphery of the U-shaped groove is in an eccentric relation to the arc portion of the outer periphery. The thickness of the arc portion in cross-section progressively decreasing on proceeding toward the open end of the U-shaped groove to make longer the arc portion contacting the through-hole of the printed circuit board. The U-shaped groove is formed with a ramp surface located inside the inner periphery near to the connection portion, connected to the bottom of the U-shaped groove and inclined to make shallower the U-shaped groove, thereby preventing the connection portion of the contact from being bent when it is being press-fitted into the through-hole of the printed circuit board.

C-shaped compliant contact

A public telephone set includes a communication enabling unit, a signal detector, a timer, and a CPU. The communication enabling unit enables incoming communication upon formation of a DC loop based on an incoming call. The signal detector detects a protocol signal from a maintenance center or a service center via the office line. The timer is started upon formation of the DC loop. The CPU instructs to send out alarm information to the maintenance or the service center via the office line when the signal detector generates a detection output during an operation of the timer.

Public telephone set

A public telephone set includes a speech circuit including transmitting and receiving amplifiers for forming a channel loop and two pairs of conductors for respectively connecting a transmitter and a receiver in a handset to the transmitting and receiving amplifiers in the speech circuit. The telephone set further includes an energization circuit having a resistor applied with a power source voltage, a latching relay for switching at least one of the transmitter and the receiver through the conductors to the speech circuit or the energization circuit, and a CPU including an internal timer for monitoring a connecting state of the handset by presence/absence of a current supplied to the energization circuit or a voltage appearing in the energization circuit when the latching relay switches at least one of the transmitter and the receiver to the energization circuit.

In a coin telephone, a self diagnosis function and an alarm information transmission function upon formation of a loop in an off-hook mode are utilized. Upon reception of a ringing signal from a maintenance control center, self diagnosis is performed. Upon detection of a failure, a content of the failure and a control number of the coin telephone are sent to the maintenance control center. A failure check for a coin telephone which is not frequently used can be performed from the telephone center without requiring an off-hook operation.

Alarm information transmission system for coin telephone

A method for controlling task processes using a minimum of energy. The task processes are divided into two or more groups in accordance with an execution priority. The individual task processes within each group are further prioritized with respect to each other. The method is driven by repetitive processing cycles. During each processing cycle, the highest priority task of the highest priority group is selected and executed. The method assumes a sleep or low power drain state in response to the completion of the execution of a selected task process or when no task process is available for processing and is returned to an operational state in response to the next processing cycle. The task process of the lower priority groups are selected at a longer execution cycle rate which are an integer multiple of the processing cycles.

Growing community of inventors

Tokyo, Japan

Yoshiaki Takeda