GB288756A - Telephone apparatus for use in connection with ladders - Google Patents

Telephone apparatus for use in connection with ladders

Info

Publication number
GB288756A
GB288756A GB264027A GB264027A GB288756A GB 288756 A GB288756 A GB 288756A GB 264027 A GB264027 A GB 264027A GB 264027 A GB264027 A GB 264027A GB 288756 A GB288756 A GB 288756A
Authority
GB
United Kingdom
Prior art keywords
bell
ladders
carter
microphone
connection
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
GB264027A
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.)
Carter & Co Nelson Ltd
Original Assignee
Carter & Co Nelson 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 Carter & Co Nelson Ltd filed Critical Carter & Co Nelson Ltd
Priority to GB264027A priority Critical patent/GB288756A/en
Publication of GB288756A publication Critical patent/GB288756A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/60—Systems for communication between relatively movable stations, e.g. for communication with lift

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Alarm Systems (AREA)

Abstract

288,756. Carter & Co. (Nelson), Ltd., and Carter, F. Jan. 29, 1927. Direct-call systems and apparatus.-Apparatus for use on ladders comprises two sets enclosed in boxes A, E adapted to be mounted on the ladder and connected by a cable mounted on a spring-drum J which hangs from the upper box by means of a hawser. The upper box (Fig. 3) contains a microphone B, loud speaker C and bell-push D. The lower box (Fig. 2) contains a bell d connected to the bell-push D and valve amplifiers G, G<1>, which are switched in alternatively by the switch H. A microphone and receiver are connected across the terminals R, K. The three wires of the cable are connected to contact rings j<1>, j<2>, j<3> carried by the spring-drum. and engaged by contacts j<4>, j<5>, j<6>.
GB264027A 1927-01-29 1927-01-29 Telephone apparatus for use in connection with ladders Expired GB288756A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB264027A GB288756A (en) 1927-01-29 1927-01-29 Telephone apparatus for use in connection with ladders

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB264027A GB288756A (en) 1927-01-29 1927-01-29 Telephone apparatus for use in connection with ladders

Publications (1)

Publication Number Publication Date
GB288756A true GB288756A (en) 1928-04-19

Family

ID=9743121

Family Applications (1)

Application Number Title Priority Date Filing Date
GB264027A Expired GB288756A (en) 1927-01-29 1927-01-29 Telephone apparatus for use in connection with ladders

Country Status (1)

Country Link
GB (1) GB288756A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3403349A1 (en) * 1984-02-01 1985-08-01 Diehl GmbH & Co, 8500 Nürnberg Detonation signal transmitter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3403349A1 (en) * 1984-02-01 1985-08-01 Diehl GmbH & Co, 8500 Nürnberg Detonation signal transmitter

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