GB985408A - Safety intercommunication devices for doors - Google Patents

Safety intercommunication devices for doors

Info

Publication number
GB985408A
GB985408A GB1418863A GB1418863A GB985408A GB 985408 A GB985408 A GB 985408A GB 1418863 A GB1418863 A GB 1418863A GB 1418863 A GB1418863 A GB 1418863A GB 985408 A GB985408 A GB 985408A
Authority
GB
United Kingdom
Prior art keywords
door
directed
doors
microphone
pair
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
GB1418863A
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.)
ARANGATH SHRIDERAN NAIR
GEOK SIONG ONG
Original Assignee
ARANGATH SHRIDERAN NAIR
GEOK SIONG ONG
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 ARANGATH SHRIDERAN NAIR, GEOK SIONG ONG filed Critical ARANGATH SHRIDERAN NAIR
Priority to GB1418863A priority Critical patent/GB985408A/en
Publication of GB985408A publication Critical patent/GB985408A/en
Priority to MY6500170A priority patent/MY6500170A/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
    • H04M1/02—Constructional features of telephone sets
    • H04M1/0291—Door telephones

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Set Structure (AREA)

Abstract

985,408. Telephone sets; interconnection systems. G. S. ONG, and A. S. NAIR. April 9, 1963, No. 14188/63. Drawings to Specification. Headings H4J and H4K. Two microphones and two receivers are mounted on a door such that one of each pair is directed to one side of the door and the other one of each pair is directed to the other side of the door whereby the occupant and a visitor to a house may communicate with each other without opening the door. A two-stage transistor amplifier having a volume control may be connected in each of the microphone-receiver circuits, the amplifier being energized from a local battery or a rectified alternating current source. The exteriorly directed microphone and receiver are preferably protected by means of a metal grill.
GB1418863A 1963-04-09 1963-04-09 Safety intercommunication devices for doors Expired GB985408A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1418863A GB985408A (en) 1963-04-09 1963-04-09 Safety intercommunication devices for doors
MY6500170A MY6500170A (en) 1963-04-09 1965-12-30 Safety intercommunication devices for doors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1418863A GB985408A (en) 1963-04-09 1963-04-09 Safety intercommunication devices for doors

Publications (1)

Publication Number Publication Date
GB985408A true GB985408A (en) 1965-03-10

Family

ID=10036613

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1418863A Expired GB985408A (en) 1963-04-09 1963-04-09 Safety intercommunication devices for doors

Country Status (2)

Country Link
GB (1) GB985408A (en)
MY (1) MY6500170A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4049911A (en) * 1976-01-06 1977-09-20 Norcon Electronics Inc. Talk-through unit with voice controlled switching with turn off delay variable from 250-500 milliseconds depending on voice amplitude
US4273956A (en) * 1977-10-03 1981-06-16 Jag International Sales Limited Audioscope project
FR2552154A1 (en) * 1983-09-21 1985-03-22 Nivet Christian Device for communicating from the inside of an apartment to the outside without having to open its access

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4049911A (en) * 1976-01-06 1977-09-20 Norcon Electronics Inc. Talk-through unit with voice controlled switching with turn off delay variable from 250-500 milliseconds depending on voice amplitude
US4273956A (en) * 1977-10-03 1981-06-16 Jag International Sales Limited Audioscope project
FR2552154A1 (en) * 1983-09-21 1985-03-22 Nivet Christian Device for communicating from the inside of an apartment to the outside without having to open its access

Also Published As

Publication number Publication date
MY6500170A (en) 1965-12-31

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