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Publication date
Application filed by Bell Telephone MfgfiledCriticalBell Telephone Mfg
Publication of CH138456ApublicationCriticalpatent/CH138456A/de
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
H04M1/31—Devices which can set up and transmit only one digit at a time by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses
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Engineering & Computer Science
(AREA)
Signal Processing
(AREA)
CH138456D1929-04-061929-04-06Wahlschalter für Telephonanlagen.
CH138456A
(de)