Masking device for selectively preventing visualization of data from a

Abstract

A data masking device having a first memory for storing information code signals convertible into visible information and a second memory containing specific code signals in locations corresponding to the code signals in the first memory which selectively are not to be visualized. Signals from each memory are simultaneously read out and a detector detects the read-out of a specific code. When the device is in a mask mode and a specific code signal is detected, the information code signal corresponding to the detected specific code is masked, i.e. it is either not visualized or else a special mark is visualized in its place. When the device is in an unmask mode, the information code signals are converted into visualized information irrespective of the detection of a specific code signal during read-out.