Sharp Kabushiki Kaisha Corporation

Michiyuki Horiguchi

Masakazu Ohashi

Yoshimitsu Matsui

Daisuke Mochizuki

The disclosure is directed to a data transmission system capable of transmitting any desired data between a plurality of terminal units connected to each other for transmitting and receiving a variety of data wherein it is characterized in that; as soon as one of these terminal units first detects a signal collision, the relevant collision signal is instantly sent to the transmission line, thus enabling all other units to correctly detect such a collision, and as a result, an overall system capability for correctly detecting any collision occurring in the transmission line can be improved significantly, resulting in the minimized error throughout data transmission operations.

Data transmission system with means for distributing collision signals

A local network system interconnects computer devices, such as cash registers, scattered in a relatively small area. The local network system includes reception control element for determining the packet format of data received from a data transmission line and forming a response packet based on the result of the determination; a transmission control element for delivering data that is to be transmitted, or the response packet, in a prescribed packet format over the transmission line, and transmission and reception control elements for controlling the transfer of transmitted and received data between the reception and transmission control elements and terminal devices. Access to the transmission line, generation of packets, data buffering, retransmission control and other operations are effected not at high level or an application program level, but at the level of an interface or data transfer control apparatus that interconnects the terminal device serving as a main system.

Data transmission control apparatus in local network systems

An in-line data communication system includes a bidirectional communication cable for connecting at least two terminal stations. A signal level compensation circuit is connected to the bidirectional communication cable for compensating for signal attenuation in the bidirectional communication cable. The signal level compensation circuit includes first and second amplifying circuits connected to each other in a parallel fashion. When a data signal is transmitted in one direction in the bidirectional communication cable, the first amplifying circuit is enabled and the second amplifying circuit is disabled. When the data signal is transmitted in the opposing direction, the first amplifying circuit is disabled and the second amplifying circuit is enabled.

Signal level compensation in an in-line data communication system

A DC power supply circuit includes a blocking oscillator circuit of the transistor saturation type, an error detection circuit for detecting difference between an output voltage level and a preselected reference level, and a control circuit. At the start of the circuit operation, the blocking oscillator circuit is controlled in the self oscillation mode, and thereafter, controlled in the separate excitation mode. The control circuit responds to an output signal of the error detection circuit and functions to lengthen an ON period of a switching transistor included in the blocking oscillator circuit when the output voltage level is lower than the preselected reference level. Contrarily, when the output voltage level is higher than the preselected reference level, the ON period of the switching transistor is shortened.

DC Power supply circuit

A power supply voltage stabilizer comprising a transformer, of which the primary winding is connected to a switching means for controlling power supply to the primary winding. An oscillator circuit is associated with the switching means in order to control on/off operation of the switching means. An abnormal overvoltage and/or overcurrent detection circuit is provided for terminating the oscillation operation of the oscillator circuit when impending overvoltage and/or overcurrent is detected.

Growing community of inventors

Nara, Japan

Michiyuki Horiguchi