Abstract: A cascade of safety switches includes safety switches for the monitoring of accesses of an automation system, at least one connection unit for the arrangement between two safety switches, and a terminator for the termination of the cascade of safety switches. Each safety switch has a first conductor and a second conductor. The first conductor includes conductor cores for transmitting signals and for receiving voltage. The second conductor includes conductor cores for receiving signals and for forwarding the voltage. The connection unit has a first circuit and a second circuit. The first circuit is provided for receiving the signals of a subsequent safety switch and for forwarding the signals of the subsequent safety switch to an upstream safety switch and the second circuit is provided for connecting the connection unit to a voltage source and to a conductor core for receiving the voltage of the subsequent safety switch.

Abstract: A cascade of safety switches includes safety switches for the monitoring of accesses of an automation system, at least one connection unit for the arrangement between two safety switches, and a terminator for the termination of the cascade of safety switches. Each safety switch has a first conductor and a second conductor. The first conductor includes conductor cores for transmitting signals and for receiving voltage. The second conductor includes conductor cores for receiving signals and for forwarding the voltage. The connection unit has a first circuit and a second circuit. The first circuit is provided for receiving the signals of a subsequent safety switch and for forwarding the signals of the subsequent safety switch to an upstream safety switch and the second circuit is provided for connecting the connection unit to a voltage source and to a conductor core for receiving the voltage of the subsequent safety switch.