Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Telephone intercommunication system providing common access to a communication line










Image Number 4 for United States Patent #3931479.

A private telephone intercommunication system including facilities for connecting the system to a telephone central office. Common supervisory means are provided to control access to a line from each station.








 
 
  Recently Added Patents
Conductor for transmitting electrical power
Autobrake and decel control built-in test equipment
Image surveillance system and method of detecting whether object is left behind or taken away
System and method for testing an integrated circuit embedded in a system on a chip
Power saving methods for wireless systems
Multi-chip package with a supporting member and method of manufacturing the same
Systems and methods for building axes, co-axes and paleo-geographic coordinates related to a stratified geological volume
  Randomly Featured Patents
Floribunda rose plant named `WEKbijou`
Device for transporting printed products
Rake head
Arrangement of a shaft with a mechanical face seal mounted thereon
Head slider, glide height checking apparatus, and glide height checking method
Intelligent system to indicate appropriate trajectories in cue sports
Vehicle external warning sound generation system and method
High frequency optical pulse source
Foldable sample display table
Paving stone