Question 1: Standard FCC Part 15 B in the B mean?
A: Actually, to be exact FCC Part 15 B should be FCC Part 15 Class B (B Class A digital device).

Class A and Class B definitions:
Class A digital device-A Class A digital device.
A digital device that is marketed for use in a commercial, industrial or business
environment, exclusive of a device which is marketed for use by the general
public or isintended to be used in the home. on the market for use in commercial, industrial or business environment, use of digital devices, but does not include the market for the general public or family use of the device.
Class B digital device-B Class A digital device.
Class B digital device. A digital device that is marketed for use in a residential
environment notwithstanding use in commercial, business and industrial
environments. Examples of such devices include, but are not limited to,
personal computers, calculators, and similar electronic devices that are
marketed for use by the general public. Note: The responsible party may also
qualify a device intended to be marketed in a commercial, business or
industrial environment as a Class B device, and in fact is encouraged to do so,
provided the device complies with the technical specifications for a Class B
digital device. In the event that a particular type of device has been found to
repeatedly cause harmful interference to radio communications, the
Commission may classify such a digital device as a Class B digital device,
regardless of its intended use. on the market not only in commercial, industrial or business environments and living conditions to be used in digital devices. Examples of such devices include (but are not limited to): personal computers, calculators, and the market for general public use similar electronic devices. Note: The duties of department can also put on the market for commercial, industrial or business environment, the device is defined as the use of Class B device; fact FCC also encouraged the move, as long as the device can meet the technical specifications for B-class devices. If the particular type of device repeatedly cause harmful interference to radio communications, the FCC may classify as a Class B digital device, regardless of its intended.
Problem 2: FCC's directory?
A: Here is the directory FCC PART 15 chapters:
Subpart A - General (general requirements)
Subpart B - Unintentional Radiators (unintentional radiator)
Subpart C - Intentional Radiators (intentionally radiator)
Subpart D - Unlicensed Personal Communications Service Devices
Subpart E - Unlicensed National Information Infrastructure Devices
Subpart F - Ultra-Wideband Operation
Subpart G - Access Broadband Over Power Line (Access BPL)

Question 3: Intentional and unintentional radiator radiator definition
A: Intentional radiator (radiator intended) - the definition. A device that intentionally generates
and emits radio frequency energy by radiation or induction. by radiation or induction that intentionally generates and emits RF (radio frequency) energy devices.
Note: infrared equipment (such as: infrared remote control) because infrared does not belong to RF (radio frequency), so it does not belong to intentionally radiator. In addition, if the infrared device clock frequency (clock frequency) is less than 9KHz, then it does not require FCC Doc test; if clock frequency (clock frequency) is greater than 9KHz, then it needs to FCC testing, must comply with
FCC Part 15.209 (Radiated emission limits .- radiation testing)
Unintentional radiator (unintentional radiator) - defined. A device that intentionally generates
radio frequency energy for use within the device, or that sends radio frequency
signals by conduction to as [FS: PAGE] sociated equipment via connecting wiring,
but which is not intended to emit RF energy by radiation or induction. intentionally generates radio frequency energy supply device for internal use or by connecting the RF signal transmitted to the equipment used, but not interested in radiation or induction to any emission of RF energy device.