IEC 61175-1:2015 provides rules for the composition of designations for the identification of signals and signal connections. This includes the designation of power supply. This part of IEC 61175 is applicable to all types of signals within an industrial system, installation and equipment and industrial products. It deals with the information aspect of signals and not with their physical implementation. This first edition cancels and replaces the second edition of IEC 61175 published in 2005 and constitutes a technical revision. It includes the following changes: an improved description of the principles for use and a strict separation between the physical aspect of a signal and its associated information, focusing on the latter. This horizontal standard is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 108.