FR2421520A1 - Intercom system using common line - compares received code with identifying code and enables amplitude modem to open communication between two posts and block others - Google Patents

Intercom system using common line - compares received code with identifying code and enables amplitude modem to open communication between two posts and block others

Info

Publication number
FR2421520A1
FR2421520A1 FR7810015A FR7810015A FR2421520A1 FR 2421520 A1 FR2421520 A1 FR 2421520A1 FR 7810015 A FR7810015 A FR 7810015A FR 7810015 A FR7810015 A FR 7810015A FR 2421520 A1 FR2421520 A1 FR 2421520A1
Authority
FR
France
Prior art keywords
posts
common line
code
open communication
intercom system
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.)
Granted
Application number
FR7810015A
Other languages
French (fr)
Other versions
FR2421520B3 (en
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.)
PHONINTER SA
Original Assignee
PHONINTER SA
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 PHONINTER SA filed Critical PHONINTER SA
Priority to FR7810015A priority Critical patent/FR2421520A1/en
Publication of FR2421520A1 publication Critical patent/FR2421520A1/en
Application granted granted Critical
Publication of FR2421520B3 publication Critical patent/FR2421520B3/fr
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/02—Arrangements for interconnection not involving centralised switching involving a common line for all parties
    • H04M9/022—Multiplex systems
    • H04M9/025—Time division multiplex systems, e.g. loop systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Small-Scale Networks (AREA)
  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)

Abstract

The intercom system has a number of posts connected on a common line (11) along which a pulse generator (10) transmits periodic series of four pulses. Each post has a keyboard (14) and logic circuit (15) which alters the pulse series to identify caller and called. A receiver (12b) of the called post compares the received code with its own identifying code and enables an amplitude modulator-demodulator (13) to open communication between posts and block out communication with other posts. The system avoids the need for a central control. More than two posts can be interconnected.
FR7810015A 1978-03-31 1978-03-31 Intercom system using common line - compares received code with identifying code and enables amplitude modem to open communication between two posts and block others Granted FR2421520A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7810015A FR2421520A1 (en) 1978-03-31 1978-03-31 Intercom system using common line - compares received code with identifying code and enables amplitude modem to open communication between two posts and block others

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7810015A FR2421520A1 (en) 1978-03-31 1978-03-31 Intercom system using common line - compares received code with identifying code and enables amplitude modem to open communication between two posts and block others

Publications (2)

Publication Number Publication Date
FR2421520A1 true FR2421520A1 (en) 1979-10-26
FR2421520B3 FR2421520B3 (en) 1980-12-19

Family

ID=9206686

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7810015A Granted FR2421520A1 (en) 1978-03-31 1978-03-31 Intercom system using common line - compares received code with identifying code and enables amplitude modem to open communication between two posts and block others

Country Status (1)

Country Link
FR (1) FR2421520A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2103187A1 (en) * 1994-10-24 1997-08-16 Gorrochategui Grajirena D Javi Two-wire communication system for interphones

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2103187A1 (en) * 1994-10-24 1997-08-16 Gorrochategui Grajirena D Javi Two-wire communication system for interphones

Also Published As

Publication number Publication date
FR2421520B3 (en) 1980-12-19

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Legal Events

Date Code Title Description
ST Notification of lapse