JPS556931A - Dial tone detecting system - Google Patents

Dial tone detecting system

Info

Publication number
JPS556931A
JPS556931A JP7928978A JP7928978A JPS556931A JP S556931 A JPS556931 A JP S556931A JP 7928978 A JP7928978 A JP 7928978A JP 7928978 A JP7928978 A JP 7928978A JP S556931 A JPS556931 A JP S556931A
Authority
JP
Japan
Prior art keywords
pulse
dial
dial tone
gate
output
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
JP7928978A
Other languages
Japanese (ja)
Other versions
JPS6046908B2 (en
Inventor
Takashi Oyamada
Akio Hikone
Tadahiko Shibuya
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 JP7928978A priority Critical patent/JPS6046908B2/en
Publication of JPS556931A publication Critical patent/JPS556931A/en
Publication of JPS6046908B2 publication Critical patent/JPS6046908B2/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
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/31—Devices which can set up and transmit only one digit at a time by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses
    • H04M1/312—Devices which can set up and transmit only one digit at a time by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses pulses produced by electronic circuits

Abstract

PURPOSE:To secure the dial transmission by detecting that the normal dial tone arrives at the dial turning time and thus to eliminate the wrong operation to the telephone set. CONSTITUTION:Dial tone reception circuit DTR converts the output of frequency selection element FL into the pulse signals. At the dial turning time, the output of gate NAND11 is turned to L with L gate OR11 turned on. The pulse signals given from DTR passes through OR11, and the first pulse drives pulse generator PG2 which generates the pulse of fixed time duration T as well as resets counter CT1. During time duration T, the pulse of the dial tone is applied to counter CT1 through gate OR12. When CT1 counts the number corresponding to the frequency of the dial tone, the input of gate NAND13 becomes H when the counting is over. In this case, if the pulse of duration T becomes H, it is changed to the detection output to the normal dial tone. Thus, the dial transmission becomes possible.
JP7928978A 1978-06-30 1978-06-30 Dial tone detection method Expired JPS6046908B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7928978A JPS6046908B2 (en) 1978-06-30 1978-06-30 Dial tone detection method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7928978A JPS6046908B2 (en) 1978-06-30 1978-06-30 Dial tone detection method

Publications (2)

Publication Number Publication Date
JPS556931A true JPS556931A (en) 1980-01-18
JPS6046908B2 JPS6046908B2 (en) 1985-10-18

Family

ID=13685692

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7928978A Expired JPS6046908B2 (en) 1978-06-30 1978-06-30 Dial tone detection method

Country Status (1)

Country Link
JP (1) JPS6046908B2 (en)

Also Published As

Publication number Publication date
JPS6046908B2 (en) 1985-10-18

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