Abstract: A circuit that protects electronic components from damage caused by current and voltage surges generated on signal or data transmission lines when an electrically energized host device is connected to or disconnected from a peripheral device. The circuit uses transistor elements to switch off or interrupt the signal or data transmission line thus protecting circuit elements from damage. The protective circuit is enabled automatically whenever the connection of ground pins between the peripheral and the host fails to be established, as opposed to enabling the protective circuit when a voltage surge or a current surge is detected by a circuit element. When the ground pins between peripheral and host are finally connected, the circuit automatically responds by allowing data and signals to be transmitted between the host and the peripheral.