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 Krone GmbhfiledCriticalKrone Gmbh
Publication of BE781389ApublicationCriticalpatent/BE781389A/fr
H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/26—Devices for calling a subscriber
H04M1/30—Devices which can set up and transmit only one digit at a time
H04M1/50—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies
Landscapes
Engineering & Computer Science
(AREA)
Signal Processing
(AREA)
Push-Button Switches
(AREA)
BE781389A1971-04-021972-03-29Dispositif pour la selection par clavier de combinaisons de signes formees chacune par deux frequences de signaux
BE781389A
(fr)