GB869895A - Improvements relating to communication apparatus - Google Patents

Improvements relating to communication apparatus

Info

Publication number
GB869895A
GB869895A GB3199956A GB3199956A GB869895A GB 869895 A GB869895 A GB 869895A GB 3199956 A GB3199956 A GB 3199956A GB 3199956 A GB3199956 A GB 3199956A GB 869895 A GB869895 A GB 869895A
Authority
GB
United Kingdom
Prior art keywords
loud
switch
speaker
amplifier
microphone
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
GB3199956A
Inventor
James Leslie Hamilton
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.)
FORESIGHT PRODUCTIONS Ltd
Original Assignee
FORESIGHT PRODUCTIONS 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 FORESIGHT PRODUCTIONS Ltd filed Critical FORESIGHT PRODUCTIONS Ltd
Priority to GB3199956A priority Critical patent/GB869895A/en
Publication of GB869895A publication Critical patent/GB869895A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R27/00—Public address systems
    • H04R27/04—Electric megaphones

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Burglar Alarm Systems (AREA)
  • Fire Alarms (AREA)
  • Alarm Systems (AREA)

Abstract

869,895. Loud-speaker systems. FORESIGHT PRODUCTIONS Ltd. Jan. 20, 1958 [Oct. 20, 1956], No. 31999/56. Class 40 (4). Loud-hailing and intercommunication equipment carried by a fireman includes a throat contact microphone 12 and a portable case 15 housing an amplifier and a loud-speaker 20. The equipment is linked to a remote station by a cable Ca which may also serve as a smoke line. Calling signals and alarm signals can be made. Microphone.-A contact microphone comprises two elements carried by a collar 13 of rod, tube or strip material which may be sprung into position. Sponge rubber covers prevent acoustic reaction. Amplifier circuits &c. (Provisional drawing).-With switch S2 closed and S1 as shown, the microphone MIC is linked to the loud-speaker SP 1 by a three-stage transistor amplifier. An alarm signal is given by a buzzer on closing switch S3. The loud-speaker SP1 is connected in parallel with a loud-speaker SP2 at a remote station over cable Ca. Loud-speaker SP2 also serves as a microphone. Switch S4 connects a buzzer to give a calling signal. Switch S1 is changed over to receive and amplify speech from the remote station. In an alternative circuit, Fig. 4, the loud-speakers SP1, SP2 and the output transformer secondaries at two similar stations are connected in series over the cable so that both loudspeakers reproduce the signals from microphones at either station. Thermionic valves V1, V2 are used for the first two amplifier stages. When switch S3 is operated, they oscillate to generate an alarm signal. Switch S2 is the amplifier on/off switch.
GB3199956A 1956-10-20 1956-10-20 Improvements relating to communication apparatus Expired GB869895A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3199956A GB869895A (en) 1956-10-20 1956-10-20 Improvements relating to communication apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3199956A GB869895A (en) 1956-10-20 1956-10-20 Improvements relating to communication apparatus

Publications (1)

Publication Number Publication Date
GB869895A true GB869895A (en) 1961-06-07

Family

ID=10331507

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3199956A Expired GB869895A (en) 1956-10-20 1956-10-20 Improvements relating to communication apparatus

Country Status (1)

Country Link
GB (1) GB869895A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311872A (en) * 1979-05-21 1982-01-19 Davis Robert P Portable voice communication system
GB2165721A (en) * 1984-10-16 1986-04-16 Charles William Dickinson A speech facility for a facemask

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311872A (en) * 1979-05-21 1982-01-19 Davis Robert P Portable voice communication system
GB2165721A (en) * 1984-10-16 1986-04-16 Charles William Dickinson A speech facility for a facemask

Similar Documents

Publication Publication Date Title
GB936570A (en) Improvements in or relating to hearing aids
DE3462386D1 (en) Hearing aid
US2214992A (en) Receiver and transmitter for telephone desk sets
GB961369A (en) Improvements in electro-acoustic transducer which is incorporated in a capsule and comprises a transistor amplifier particularly for telephone handsets
GB858678A (en) Loudspeaking telephone using transistors
GB869895A (en) Improvements relating to communication apparatus
GB761169A (en) Improvements in or relating to hearing aids
GB791895A (en) Improvements in or relating to telephone sets
GB776280A (en) Improvements in or relating to moving coil loudspeakers and microphones
GB1065326A (en)
GB779156A (en) A remote control device for use with apparatus incorporating a loud speaker
GB638930A (en) Improvements in and relating to radio and intercommunication apparatus and systems
GB620695A (en) Improvements in or relating to amplifying devices for use with telephone sets
GB795144A (en) Improvements in or relating to loud-speaking telephone apparatus
GB956113A (en) Improvements in or relating to hearing aids
GB962780A (en) Deaf aid
GB936756A (en) Improvements in or relating to loudspeaking telephone systems
GB973479A (en) Improvements in hearing aids
GB984889A (en) Improvements in or relating to electro-acoustic transducers
ES39054U (en) Listen pillow (Machine-translation by Google Translate, not legally binding)
GB862262A (en) Improvements connected with loudspeaking intercommunication systems
GB716055A (en) Improvements in and relating to sound reproduction
GB947426A (en) Improvements in or relating to two-way intercommunication systems
CA569433A (en) Telephone handset terminating and amplifier circuit
GB860938A (en) Improvements in and relating to loudspeakers