A cold cathode discharge device with high efficiency of light emission and long life is prepared by a cold cathode having both high secondary electron emission and anti-spattering property. A rational spatial relationship exists between the first and second virtual grates. Each of the forward facet and rearward portion has a length and a slope. Moreover, the port bypass circuit is adapted to receive a data signal from an input port of the circuit module, recondition the data signal received from the input port, and transmit the reconditioned data signal received from the input port to a third output port of the circuit module. Concave portions are disposed each between a corresponding pair of the adjacent holes on the end face portion. The selector selects the first data scrambler to scramble the first data during normal operations.