For bypassing a computer system coupled between first and second network links, the computer system executes a software which provides a predetermined control signal on a control line. The control line is polled by a bypass device that will cause the computer system to be bypassed when said control signal is not present on the control line. The control signal may be in the form of periodic pulses and a bypassing is caused when a pulse is not received on the control line within a predetermined period of time.