JPS57171858A - Concealing system between terminal equipments - Google Patents

Concealing system between terminal equipments

Info

Publication number
JPS57171858A
JPS57171858A JP5766581A JP5766581A JPS57171858A JP S57171858 A JPS57171858 A JP S57171858A JP 5766581 A JP5766581 A JP 5766581A JP 5766581 A JP5766581 A JP 5766581A JP S57171858 A JPS57171858 A JP S57171858A
Authority
JP
Japan
Prior art keywords
switchboard
information
concealed
concealing device
converted
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.)
Pending
Application number
JP5766581A
Other languages
Japanese (ja)
Inventor
Shinichi Miwa
Shinjiro Suzuki
Shigeki Tanaka
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP5766581A priority Critical patent/JPS57171858A/en
Publication of JPS57171858A publication Critical patent/JPS57171858A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication

Abstract

PURPOSE:To reduce the maintenance cost and to asure the preservative measures by eliminating the need for a concealing device between extensions of the switchboard of the own station, by connecting a switchboard and a terminal equipment with an optical fiber cable, and by controlling the concealing device and the switchboard from the center by installing them in one place. CONSTITUTION:Transmitting information is subjected to an electrooptic conversion in a terminal T, and the converted optical signal is supplied to a switchboard A or B through an optical fiber cable C. The optical transmitting information is again converted into an electric signal at the switchboard A or B, and the signal is divided into two, information to be concealed and information not to be concealed. The information to be concealed is supplied to a concealing device CRY and each information is transmitted to a repeating transmission line (t) after they are converted into ciphers. The information not to be concealed is directly transmitted to the opposite switchboard B or A through a repeating transmission line (t'). The concealing device CRY is installed in the same place (a) or (b) where each switchboard A or B is installed, and thus the central control of them is made easier and the preservative measures are assured.
JP5766581A 1981-04-16 1981-04-16 Concealing system between terminal equipments Pending JPS57171858A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5766581A JPS57171858A (en) 1981-04-16 1981-04-16 Concealing system between terminal equipments

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5766581A JPS57171858A (en) 1981-04-16 1981-04-16 Concealing system between terminal equipments

Publications (1)

Publication Number Publication Date
JPS57171858A true JPS57171858A (en) 1982-10-22

Family

ID=13062195

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5766581A Pending JPS57171858A (en) 1981-04-16 1981-04-16 Concealing system between terminal equipments

Country Status (1)

Country Link
JP (1) JPS57171858A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987007101A1 (en) * 1986-05-09 1987-11-19 Raphael Tobias Concealing reproduced relayed messages

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4208545A (en) * 1954-05-24 1980-06-17 Teletype Corporation Secrecy system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4208545A (en) * 1954-05-24 1980-06-17 Teletype Corporation Secrecy system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987007101A1 (en) * 1986-05-09 1987-11-19 Raphael Tobias Concealing reproduced relayed messages

Similar Documents

Publication Publication Date Title
AU584673B2 (en) An optical communication system
GB8924839D0 (en) Transmission of broadband signals
DE3852139T2 (en) Two-way communication systems.
TW236059B (en) An extendible round robin local area hub network
JPS57171858A (en) Concealing system between terminal equipments
JPS5736305A (en) Multivalue control system
JPS56114450A (en) Signal transmission system
CA1241993A (en) Closed loop transmission system
JPS5617537A (en) Information transmitting system using optical data bus line
JPS57173236A (en) Composite loop transmitter
JPS56138346A (en) Control system for multipoint line
DE3462651D1 (en) Switching system
JPS6436239A (en) Multiplex transmission equipment
KR890001606B1 (en) Signal transmission system
JPS6413843A (en) Supervisory and control system for optical repeater
GB2133955B (en) Transmission systems for transmitting signals over power distribution networks
JPS5334081A (en) Time sharing multiplex transmission system
JPS53131706A (en) Automatic telephone exchange system
JPS5763945A (en) Single-core two-way optical communication system
JPS57166751A (en) Separated system transmission device
JPS55114049A (en) Optical fiber two-way transmitter
JPS5750143A (en) Optical cable communication system
JPS57132441A (en) Data way
JPS57148435A (en) Optical data way system
JPS5797741A (en) Optical transmission device with light distributing function