GB1176448A - Improvements in or relating to Voice Frequency Signalling Systems - Google Patents

Improvements in or relating to Voice Frequency Signalling Systems

Info

Publication number
GB1176448A
GB1176448A GB2348868A GB2348868A GB1176448A GB 1176448 A GB1176448 A GB 1176448A GB 2348868 A GB2348868 A GB 2348868A GB 2348868 A GB2348868 A GB 2348868A GB 1176448 A GB1176448 A GB 1176448A
Authority
GB
United Kingdom
Prior art keywords
voice frequency
relating
speech
signalling
signalling systems
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.)
Expired
Application number
GB2348868A
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.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone 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 Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Publication of GB1176448A publication Critical patent/GB1176448A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/46—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current

Abstract

1,176,448. Speech immunity signalling. NIPPON TELEGRAPH & TELEPHONE PUBLIC CORP. 17 May, 1968 [22 May, 1967], No. 23488/68. Heading H4R. In a voice frequency signalling system in which frequency components other than the signalling frequencies are used as guard signals to prevent operation by signal imitation in speech, the frequency characteristic of the signal applied to the guard circuit is varied by emphasizing the frequencies in the region of the third formant of normal speech, i.e. the region about 3 kHz.
GB2348868A 1967-05-22 1968-05-17 Improvements in or relating to Voice Frequency Signalling Systems Expired GB1176448A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3213167 1967-05-22

Publications (1)

Publication Number Publication Date
GB1176448A true GB1176448A (en) 1970-01-01

Family

ID=12350322

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2348868A Expired GB1176448A (en) 1967-05-22 1968-05-17 Improvements in or relating to Voice Frequency Signalling Systems

Country Status (4)

Country Link
DE (1) DE1762312B1 (en)
FR (1) FR1566000A (en)
GB (1) GB1176448A (en)
SE (1) SE329192B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3798382A (en) * 1972-05-22 1974-03-19 Ford Ind Inc Voice-monitoring control circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3798382A (en) * 1972-05-22 1974-03-19 Ford Ind Inc Voice-monitoring control circuit

Also Published As

Publication number Publication date
DE1762312B1 (en) 1970-09-03
FR1566000A (en) 1969-05-02
SE329192B (en) 1970-10-05

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