Similar in many respects to the Spaceograph devices found on Mongo, a televisor allows for 2 way communication where both parties have access to a unit. The full size units come replete with a screen for visual communication also, although smaller, more basic models only capable of audio communication can be found in Stratosleds.
Operation of the unit is via large knobs which require delicate adjustments.
The exact workings of televisors are not clear; they do not seem to rely on any type of camera for visual input, as they appear capable of picking up images from any given point. For example, a televisor is able to tune in on Flash Gordon's exact location almost instantaneously, even if the operator of the televisor does not know where on the planet Mars Flash actually is.
Televisors appear to use the 4:3 screen dimensions as opposed to 16:9 widescreen format.