The ability of devices and systems to operate in their electromagnetic environment without impairing their functions and without faults and vice versa, i. e. to ensure that operation does not influence the electromagnetic environment to the extent that the functions of other devices and systems are adversely affected. 

Precompliance measurements are intended to give an approximation of the EMI performance of the EUT. The cost of performing precompliance tests is a fraction of full compliance measurements. The more attention to detail, such as a good ground plane and minimizing the number of reflective objects in the measurement area, the better the accuracy of the measurements.

Full compliance measurements require the use of a receiver that meets the requirements set forth in the CISPR 1 part 16 documents, a qualified open area test site, and an antenna tower and turntable to maximize the signals from the EUT. Great effort is taken to get the best accuracy and repeatability.