Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • 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
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
  • H04M1/6008—Substation equipment, e.g. for use by subscribers including speech amplifiers in the transmitter circuit
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M19/00—Current supply arrangements for telephone systems
  • H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone
  • H04M19/04—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone the ringing-current being generated at the substations

Landscapes

• Engineering & Computer Science (AREA)
• Signal Processing (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=4561422

Family Applications (1)

Country Status (3)

• 0
  • BE BE556704D patent/BE556704A/xx unknown
• 1956
  • 1956-04-19 CH CH344450D patent/CH344450A/de unknown
  • 1956-12-05 CH CH348727D patent/CH348727A/de unknown
• 1957
  • 1957-04-18 FR FR1174284D patent/FR1174284A/fr not_active Expired

Also Published As

Similar Documents