Purchasers can use the test methods described in this standard to determine whether a particular piece of equipment meets the essential requirements. Procurement officials may also refer to this standard in their purchasing requirements. Compliance with the requirements of the standard may be attested to by an independent laboratory or guaranteed by the vendor. For the purposes of this standard, FM transmitters are classified by their operating frequencies: Type I are transmitters which operate in the 25-50 MHz band; Type II are transmitters which operate in the 150-174 MHz band; and, Type III are transmitters which operate in the 400-512 MHz band. 2 references, bibliography.