The Farnsworth is a two-way audio and video communications device invented by Philo Farnsworth in 1929, soon after the invention of the television. They're used by Warehouse agents because they are on their own secure frequency spectrum and can't be cracked, hacked, tapped, or otherwise "broken".
Philo Taylor Farnsworth was an American inventor best known for inventing the first fully electronic television system, including the first working electronic image pickup device (video camera tube). He was the first person to demonstrate fully electronic television to the public.
The Farnsworth has been a tool long used by agents working for the Warehouse.
How it WorksEdit
Incoming transmissions sound a buzzing to alert the possessor of this artifact. To start the transmission, the device is opened like a book and the right-most button located just below the red lamp is pushed. Closing the device ends the transmission, as does pushing the button a second time. How transmissions actually operate, however, is currently unknown, though based on the fact that the device was developed in the same era as the first television, radio waves are a reasonable surmise. It has, however, been categorically stated that Farnsworths operate on an "unhackable frequency", whatever that may require. They were designed to be able to work anywhere, even if the user is deep underground.
Real World ConnectionsEdit
Most likely, the Farnsworth Communicator uses short-wave radio signals, which can travel enormous distances by 'bouncing' their signals off the electromagnetically-charged ionosphere which surrounds the planet. Real-Life Shortwave radios function in this manner, though they tend to produce a better signal when used at night (when the Sun's rays aren't interfering with the device). It can be hypothesized that Philo Farnsworth may have created means of making shortwave radio signals more powerful or efficient, so that they could be used at any time of the day at any distance on the planet.