Standard Part FCC 15 B in B representative of the meaning of
In fact, it is accurate to say that the Part FCC 15 FCC should be Part Class 15 B B (B level digital devices).

Definition of A Class and B Class:

Class A digital device
A digital device that is marketed for use in a commer cial, industrial or business　environment, exclusive of a device which is marketed for use by the general public　or is intended to be used in the home.

Class B 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。

PART FCC 15 contents of the contents of the chapter:
Subpart A – General
Subpart B - Unintentional Radiators
Subpart C - Intentional Radiators
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)

Technical specifications can also be used in the market not only for the commercial, industrial or business environment and the living environment of digital device. The device examples include (but are not limited to): personal computers, calculators and other market for general public use similar electronic device. Note: the responsibilities of departments to put on the market for commercial, industrial or business environment in the use of the device is defined as class B device; in fact the FCC also encouraged the move, as long as the device can meet the class B device. If a certain type of device repeatedly to radio communication produce harmful interference, the FCC may be classified as a class B digital device, regardless of its use.