MIL-STD-461 is a Military Standard that describes how to test equipment for electromagnetic compatibility. MIL-STD-461 compliance typically is not required outside the US military. Often this standard is used for the testing of commercial products as well.
MIL-STD-461 has been active since 1967 and has undergone several major revisions. These changes where largely caused by the rapidly increasing use of electronics and advancements in technology. Some legacy programs may still refer to earlier versions of this document in order to ensure that there has been no impact since the original compliance report. In 1999, MIL-STD-462 was combined with MIL-STD-461D into MIL-STD-461E