Section 106(6): the owner of copyright under this title has the exclusive rights to do and to authorize any of the following: [...] in the case of sound recordings, to perform the copyrighted work publicly by means of a digital audio transmission
Section 114(d1 Cii): The performance of a sound recording publicly by means of a digital audio transmission, other than as a part of an interactive service, is not an infringement of section 106(6) if the performance is part of [...] a transmission within a business establishment, confined to its premises or the immediately surrounding vicinity
So, I would assume that an interactive broadcast of digital music at work would not be considered to be fair use and that it would be a violation of the law.
Excerpts from the U.S. Code:
So, I would assume that an interactive broadcast of digital music at work would not be considered to be fair use and that it would be a violation of the law.