The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 26, 1976
Filed:
Apr. 02, 1975
Cristiano Dall'Olio, Turin, IT;
Enzo Garetti, Turin, IT;
Abstract
Message transmission between subscriber stations served by different central offices takes place via frequency-division channels through the intermediary of couplers recognizing different line signals, specifically pulse sequences modulating the amplitude of a fixed-frequency oscillation on a test wire, to initiate certain switching operations. A processor, responding to these signals either upon initiation of a connection or in the course thereof, summons an available modem which is temporarily connected to the associated coupler and emits a characteristic a-c signal picked up by a remote coupler at another exchange which thereupon causes its processor to connect another modem to it, to the exclusion of any subscriber line to which that coupler may have been previously connected. The two modems then intercommunicate and work into respective logic networks which, under their control, carry out the requisite switching operations whereupon the modems are released upon establishment or re-establishment of the desired connection.