Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Cordless telephone










Image Number 8 for United States Patent #4053717.

A cordless telephone including a Touch-tone signal generator module including ten buttons for initiating the generation of telephone switching signals representing ten numeric characters and two additional buttons; one of which is used for switching the cordless telephone into and out of a standby mode of operation in which a ring signal may be received and detected, and the other of which is used for providing off-hook and on-hook switching functions.The telephone lines are seized in response to a discrete control signal transmitted from the cordless telephone, which discrete control signal has a low freqency below an audio frequency band within which audio signals and switching signals transmitted from the cordless telephone are passed onto the telephone lines. These signals are transmitted by frequency modulation.The discrete control signal is summed with signals within the audio frequency band to provide a composite signal and an RF carrier signal is frequency modulated with the composite signal. Intermodulation between the discrete control signal and the audio and switching signals is prevented by providing a linear frequency deviation in response to amplitude variations in the composite signal.








 
 
  Recently Added Patents
Method to quantify siRNAs, miRNAs and polymorphic miRNAs
Polarization-coupled ferroelectric unipolar junction memory and energy storage device
Using location based services for determining a calling window
System and method for providing a path avoidance feature in a network environment
Quantitative sleep analysis system and method
Triple-action pest control formulation and method
Substrate and patterning device for use in metrology, metrology method and device manufacturing method
  Randomly Featured Patents
Method of protecting metals against corrosion
Network transmission circuit control method and system
4U fluorescent tube
Bendable, extendable hairbrush with removable brush head
Cooking appliance
Substituted pyridinyl esters of 2-(1-oxoalkyloxy)ethyl carbamic acid
System and method for bi-directional mapping between customer identity and network elements
Protected dimming control interface for an electronic ballast
Method and apparatus for reading NAND flash memory array
Drivetrain for an electric vehicle