Abstract: A display system for showing incoming call messages is introduced. The display system includes a monitor, a telephone plug coupled to a telephone signal source, and a microprocessor for controlling the display to show an incoming call message when an incoming call signal is received from the telephone signal source. The display enables users to notice incoming calls without disturbances of ring tones.

Abstract: A digital switch whose mechanism includes: a button, a microprocessor and a memory unit is provided. When the power supply is connected, the microprocessor outputs a control signal signifying an on/off status according to the digital switch status stored in the memory unit. When the user presses the button, the microprocessor reads the content values of the memory unit, reverses and stores it, and then outputs the control signal signifying an on/off status accordingly. When the power supply is turned off, the content of the memory unit will not be erased, such that the on/off status stored will not be altered. When the power supply is resumed, the digital switch status will remain the same as what it was when the power was turned off. The invention has the advantages of saving hardware space and reducing costs.