The KEY-PLUGs store the configuration data of a SCALANCE W component. Additional security features and iFeatures are enabled as well.

In addition to this, if there is a fault on a module, the module can be replaced simply and quickly without needing to reconfigure the replacement device and without specially trained personnel. If a device needs to be replaced, the KEY-PLUG is simply removed from the failed component and plugged into the replacement device. The replacement device installed in the network now starts up automatically with the same device configuration as the failed device.