JPS55154854A - Data communication unit - Google Patents

Data communication unit

Info

Publication number
JPS55154854A
JPS55154854A JP6259579A JP6259579A JPS55154854A JP S55154854 A JPS55154854 A JP S55154854A JP 6259579 A JP6259579 A JP 6259579A JP 6259579 A JP6259579 A JP 6259579A JP S55154854 A JPS55154854 A JP S55154854A
Authority
JP
Japan
Prior art keywords
signal
transmission request
unit
state
transmission
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP6259579A
Inventor
Kenzo Iioka
Noboru Okazaki
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP6259579A priority Critical patent/JPS55154854A/en
Publication of JPS55154854A publication Critical patent/JPS55154854A/en
Application status is Granted legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path

Abstract

PURPOSE:To make it possible to release a transmission request state automatically by detecting a fault by a unit itself, by supervising the connection time of the transmission request state. CONSTITUTION:By using transmission-request ON signal 31, data communication unit 21 sends out a command, placing transmission request signal 37 in an ON state, to transmission request signal controller 25. At this time, counter 27 starts counting. After transmission request precessing, unit 21 starts sending data. On the end of the data transmission, transmission request OFF command signal 32 is used to send a command, placing signal 37 in an OFF state, to unit 25. If a fault occurs and signal 37 stays ON for a fixed time or more, signal 36 is sent out since the value of counter 27 exceeds the maximum time value in register 28, so that unit 25 forces signal 37 to turn OFF. Consequently, a bad influence on other data communication units connected to communication circuit 7 can be prevented.
JP6259579A 1979-05-23 1979-05-23 Data communication unit Granted JPS55154854A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6259579A JPS55154854A (en) 1979-05-23 1979-05-23 Data communication unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6259579A JPS55154854A (en) 1979-05-23 1979-05-23 Data communication unit

Publications (1)

Publication Number Publication Date
JPS55154854A true JPS55154854A (en) 1980-12-02

Family

ID=13204825

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6259579A Granted JPS55154854A (en) 1979-05-23 1979-05-23 Data communication unit

Country Status (1)

Country Link
JP (1) JPS55154854A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5966243A (en) * 1982-10-08 1984-04-14 Hitachi Ltd Data communication system
JPS60158360U (en) * 1984-03-29 1985-10-22
JPS61230539A (en) * 1985-04-05 1986-10-14 Nippon Telegr & Teleph Corp <Ntt> Bus type transfer system fault detecting and display device
JPS6367699A (en) * 1986-09-09 1988-03-26 Nohmi Bosai Kogyo Co Ltd Signal transmission circuit for disaster prevention equipment
JPS6472697A (en) * 1987-09-14 1989-03-17 Chubu Electric Power Device for automatizing distribution line
JPH03241942A (en) * 1990-02-20 1991-10-29 Mitsubishi Electric Corp Data communication system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5966243A (en) * 1982-10-08 1984-04-14 Hitachi Ltd Data communication system
JPS60158360U (en) * 1984-03-29 1985-10-22
JPS61230539A (en) * 1985-04-05 1986-10-14 Nippon Telegr & Teleph Corp <Ntt> Bus type transfer system fault detecting and display device
JPS6367699A (en) * 1986-09-09 1988-03-26 Nohmi Bosai Kogyo Co Ltd Signal transmission circuit for disaster prevention equipment
JPS6472697A (en) * 1987-09-14 1989-03-17 Chubu Electric Power Device for automatizing distribution line
JPH03241942A (en) * 1990-02-20 1991-10-29 Mitsubishi Electric Corp Data communication system
JPH0761076B2 (en) * 1990-02-20 1995-06-28 三菱電機株式会社 Data communication system

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