Currents that are inductively coupled into the long cables found in industrial environments by motors switching on and off, electrostatic discharge (ESD), or nearby lightning strikes can cause rapid changes in ground potential, often as large as hundreds, or thousands, of volts. When this occurs, the logic-level switching signal expected by the remote system would be superimposed on a high voltage with respect to its local ground. Without isolation, this voltage could corrupt the signal or damage the system. Referring all devices connected to the bus to a single ground will protect the system against this destructive energy, and isolating the devices will prevent ground loops and electrical surges. To completely isolate the system, all signal lines and power supplies must be isolated. An isolated dc-to-dc converter can provide power supply isolation, while the iCoupler digital isolator provides the signal isolation.