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.)
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Nokia Spain SA
Original Assignee
Alcatel Espana SA
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Publication date
Application filed by Alcatel Espana SAfiledCriticalAlcatel Espana SA
Publication of ES320740A1publicationCriticalpatent/ES320740A1/en
Method of signaling by keyboard at voice frequency, particularly for the transmission of information items to dial the numbers between subscriber telephone sets and the central one, characterized in that the key signals are formed by means of a push button signal (for example , a short interruption of the loop) and, for a combination of signal immune frequency to the conversation (for example a key of 2 x 1 of four) and because the evaluation is made selectively by receivers of vocal frequency impunes to the conversation (TonE1) thus omitting the signal of the key, or by normal voice frequency receivers (TonE2) that are connected arranged for operation through said key signal (SE). (Machine-translation by Google Translate, not legally binding)
ES0320740A1964-12-151965-12-14Signaling method for keyboard to vocal frequency. (Machine-translation by Google Translate, not legally binding)
ExpiredES320740A1
(en)
Method of marking by keyboard in vocal frequency without marking signal supervision of continuous current. (Machine-translation by Google Translate, not legally binding)