All equipment must be tested to demonstrate compliance with the relevant part of Title 47 of US Code of Federal Regulations (47CFR).
Verification is the procedure followed by unintentional transmitters - that is equipment that radiates radio frequency energy as a by-product of what it does, rather than to communicate.
Examples of equipment subjected to verification include Scientific and Medical (ISM) equipment; business Class A computer equipment; TV and FM receivers.
Declaration of Conformity is a similar, but slightly more onerous procedure for unintentional transmitters designed to be used in the home.
Examples include Class B personal computers and peripherals; CB receivers; super-regenerative receivers; TV interface devices.
Certification is the process that must be applied to Radio Transmitters, including mobile phones, Bluetooth, WiFi, WiMAX, microwave transmitters and warlike talkies.
Certification requires specific tests to be completed and results filed with the FCC along with details of the product certified such as Schematic Diagrams, Parts Lists, label information, tune-up information and user manuals.
Certification is required for both licensed unlicensed devices: A Licensed device is one that can only be operated under a separate license issued by the FCC to the operator of the service - examples include cellular phones and base stations.
An unlicensed device is one that can be bought by the general public and used anywhere at anytime - examples include WiFi and Bluetooth.
There are strict rules covering the amount of testing required for unlicensed devices to demonstrate compliance, but there are no such rules for licensed devices.
For a licensed device that operates in a number of modes and/or under a number of different parts of 47CFR, the use of a carefully constructed FCC Test Plan can greatly reduce test time and cost and reduce time to market.