JPS556938A - Dial number control system - Google Patents

Dial number control system

Info

Publication number
JPS556938A
JPS556938A JP7929878A JP7929878A JPS556938A JP S556938 A JPS556938 A JP S556938A JP 7929878 A JP7929878 A JP 7929878A JP 7929878 A JP7929878 A JP 7929878A JP S556938 A JPS556938 A JP S556938A
Authority
JP
Japan
Prior art keywords
pulse
dial
case
dial tone
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
JP7929878A
Other languages
Japanese (ja)
Other versions
JPS5830784B2 (en
Inventor
Takashi Oyamada
Akio Hikone
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.)
Tamura Electric Works Ltd
Original Assignee
Tamura Electric Works 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 Tamura Electric Works Ltd filed Critical Tamura Electric Works Ltd
Priority to JP53079298A priority Critical patent/JPS5830784B2/en
Publication of JPS556938A publication Critical patent/JPS556938A/en
Publication of JPS5830784B2 publication Critical patent/JPS5830784B2/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/66—Substation equipment, e.g. for use by subscribers with means for preventing unauthorised or fraudulent calling
    • H04M1/677—Preventing the dialling or sending of predetermined telephone numbers or selected types of telephone numbers, e.g. long distance numbers

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Signal Processing (AREA)
  • Prepayment Telephone Systems (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)

Abstract

PURPOSE:To block the wrong call caused by the dial transmission by detecting the dial pulse to count the pulse row corresponding to the dial pulse and in case the count result is corresponding to the specified number. CONSTITUTION:Frequency selection element FL is converted into the pulse signal featuring the cycle according to the frequency of the dial tone via waveform shaping circuit WF. The pulse given from dial tone reception circuit DTR generates the pulse of time duration T via OR11 and pulse generator PG2 and also resets counter CT1. The pulse signals of the dial tone are counted by counter CT1 via OR12. And the input of NAND13 is set at the H level only when the counting completes. In this case, FF3 is reset only when the pulse output of time duration T comletes to enable the dial transmission. The matching of the timing is not obtained in case the dial tone is not normal with different frequency. Accorddingly, FF3 is never reset to block the dial transmission.
JP53079298A 1978-06-30 1978-06-30 Dial number control method Expired JPS5830784B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP53079298A JPS5830784B2 (en) 1978-06-30 1978-06-30 Dial number control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP53079298A JPS5830784B2 (en) 1978-06-30 1978-06-30 Dial number control method

Publications (2)

Publication Number Publication Date
JPS556938A true JPS556938A (en) 1980-01-18
JPS5830784B2 JPS5830784B2 (en) 1983-07-01

Family

ID=13685929

Family Applications (1)

Application Number Title Priority Date Filing Date
JP53079298A Expired JPS5830784B2 (en) 1978-06-30 1978-06-30 Dial number control method

Country Status (1)

Country Link
JP (1) JPS5830784B2 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50134708A (en) * 1974-04-15 1975-10-25

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50134708A (en) * 1974-04-15 1975-10-25

Also Published As

Publication number Publication date
JPS5830784B2 (en) 1983-07-01

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