GB1306701A - Telephone selection circuit - Google Patents

Telephone selection circuit

Info

Publication number
GB1306701A
GB1306701A GB275570A GB275570A GB1306701A GB 1306701 A GB1306701 A GB 1306701A GB 275570 A GB275570 A GB 275570A GB 275570 A GB275570 A GB 275570A GB 1306701 A GB1306701 A GB 1306701A
Authority
GB
United Kingdom
Prior art keywords
ringing
code
discriminator
connection
substation
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
GB275570A
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.)
Oberholzer M J
Original Assignee
Oberholzer M J
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 Oberholzer M J filed Critical Oberholzer M J
Publication of GB1306701A publication Critical patent/GB1306701A/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
    • H04M1/64—Automatic arrangements for answering calls; Automatic arrangements for recording messages for absent subscribers; Arrangements for recording conversations
    • H04M1/65—Recording arrangements for recording a message from the calling party
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/66—Substation equipment, e.g. for use by subscribers with means for preventing unauthorised or fraudulent calling
    • H04M1/663—Preventing unauthorised calls to a telephone set
    • H04M1/665—Preventing unauthorised calls to a telephone set by checking the validity of a code

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
  • Telephonic Communication Services (AREA)

Abstract

1306701 Substation apparatus M J OBERHOLZER 20 Jan 1970 [21 Jan 1969] 2755/70 Heading H4K A substation includes a discriminator adj ustable to select a ringing code and arranged to connect calls using the preselected ringing code to a telephone instrument and to connect calls not using said code to an automatic answering machine. As described a caller can obtain a connection to the telephone instrument only if he is aware of the code sequence to which the discriminator is set. The caller must establish a connection to the substation, release the connection after a predetermined ringing duration and re-establish the connect after a further predetermined period. As described the discriminator is a logic circuit including variable delay monostable multivibrators used to test the duration of the ringing and silence intervals. In a modification one monostable is replaced by a bi-stable and a variable counter which counts ringing signals.
GB275570A 1969-01-21 1970-01-20 Telephone selection circuit Expired GB1306701A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6900963A NL6900963A (en) 1969-01-21 1969-01-21

Publications (1)

Publication Number Publication Date
GB1306701A true GB1306701A (en) 1973-02-14

Family

ID=19805922

Family Applications (1)

Application Number Title Priority Date Filing Date
GB275570A Expired GB1306701A (en) 1969-01-21 1970-01-20 Telephone selection circuit

Country Status (6)

Country Link
BE (1) BE744748A (en)
CH (1) CH527530A (en)
DE (1) DE2002160A1 (en)
FR (1) FR2028833A1 (en)
GB (1) GB1306701A (en)
NL (1) NL6900963A (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3793487A (en) * 1971-11-22 1974-02-19 J Kilby System for screening telephone calls
JPS62163445A (en) * 1986-01-14 1987-07-20 Mitsubishi Electric Corp Telephone switching device

Also Published As

Publication number Publication date
FR2028833A1 (en) 1970-10-16
BE744748A (en) 1970-07-01
CH527530A (en) 1972-08-31
DE2002160A1 (en) 1970-09-03
NL6900963A (en) 1970-07-23

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee