JPS57211853A - Information transmitting device - Google Patents

Information transmitting device

Info

Publication number
JPS57211853A
JPS57211853A JP56097825A JP9782581A JPS57211853A JP S57211853 A JPS57211853 A JP S57211853A JP 56097825 A JP56097825 A JP 56097825A JP 9782581 A JP9782581 A JP 9782581A JP S57211853 A JPS57211853 A JP S57211853A
Authority
JP
Japan
Prior art keywords
calling signal
calling
signal
central
devices
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.)
Pending
Application number
JP56097825A
Other languages
Japanese (ja)
Inventor
Hiroyoshi Nakajima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
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 Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP56097825A priority Critical patent/JPS57211853A/en
Publication of JPS57211853A publication Critical patent/JPS57211853A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q9/00—Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
    • H04Q9/08—Calling by using continuous ac
    • H04Q9/12—Calling by using continuous ac using combinations of frequencies

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Small-Scale Networks (AREA)
  • Communication Control (AREA)

Abstract

PURPOSE:To produce an economical transmission system by reducing the number of receiving devices for calling signals from respective terminals which have been ordinally accomodated in a central office corresponding to the number of terminals and using a calling signal receiving device in common by time-sharing technology. CONSTITUTION:Terminal devices A and B are provided with calling signal transmitting devices 7-1 and 7-2 respectively. If data are to be transmitted from the terminal device A to a central device, a data from said calling signal transmitting device is modulated by a carrier f2-1 and sent to a transmission line L-1. The central device C receives said signal through an insulating transformer 4-1, selects the signal f2-1 through a filter and leads the selected signal to a scanner 9. Since the scanner 9 scans signals always at a prescribed period, the calling signal from the terminal device A is detected by a calling signal receiving device accomodated in common in the central device C. In the same manner, a calling signal modulated by frequency f2-2 in the terminal device B can be detected by the calling signal receiving device 10.
JP56097825A 1981-06-23 1981-06-23 Information transmitting device Pending JPS57211853A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56097825A JPS57211853A (en) 1981-06-23 1981-06-23 Information transmitting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56097825A JPS57211853A (en) 1981-06-23 1981-06-23 Information transmitting device

Publications (1)

Publication Number Publication Date
JPS57211853A true JPS57211853A (en) 1982-12-25

Family

ID=14202498

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56097825A Pending JPS57211853A (en) 1981-06-23 1981-06-23 Information transmitting device

Country Status (1)

Country Link
JP (1) JPS57211853A (en)

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