GB875341A - Telephone circuit - Google Patents

Telephone circuit

Info

Publication number
GB875341A
GB875341A GB10099/60A GB1009960A GB875341A GB 875341 A GB875341 A GB 875341A GB 10099/60 A GB10099/60 A GB 10099/60A GB 1009960 A GB1009960 A GB 1009960A GB 875341 A GB875341 A GB 875341A
Authority
GB
United Kingdom
Prior art keywords
line
diode
party
switched
station
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
GB10099/60A
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.)
NEC Corp
Original Assignee
Nippon Electric Co 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 Nippon Electric Co Ltd filed Critical Nippon Electric Co Ltd
Publication of GB875341A publication Critical patent/GB875341A/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
    • H04M1/68—Circuit arrangements for preventing eavesdropping
    • H04M1/70—Lock-out or secrecy arrangements in party-line systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q5/00—Selecting arrangements wherein two or more subscriber stations are connected by the same line to the exchange

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Interface Circuits In Exchanges (AREA)

Abstract

875,341. Party-line systems. NIPPON ELECTRIC CO. Ltd. March 22, 1960 [April 23, 1959], No. 10099/60. Class 40 (4). In a party-line sub-station a diode 4 having a characteristic of the form shown in Fig. 1 is connected in series with line when the switchhook is actuated. The diode, which may be of the PNPN type, is switched from the normal high-resistance state to a low-resistance state by the line voltage which exceeds VB and remains in that condition throughout the call. In consequence the diode at another sub-station 6 cannot be switched and listening in is prevented.
GB10099/60A 1959-04-23 1960-03-22 Telephone circuit Expired GB875341A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP875341X 1959-04-23

Publications (1)

Publication Number Publication Date
GB875341A true GB875341A (en) 1961-08-16

Family

ID=13917639

Family Applications (1)

Application Number Title Priority Date Filing Date
GB10099/60A Expired GB875341A (en) 1959-04-23 1960-03-22 Telephone circuit

Country Status (1)

Country Link
GB (1) GB875341A (en)

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