Section 13(a)(2) as originally enacted in 1938 exempted any employee “engaged in” any retail or service establishment. The 1949 amendments to that section, however, as contained in section 13(a)(2) and (4) exempted any employee “employed by” any establishment described in those exemptions. The 1961 and 1966 amendments retained the “employed by” language of these exemptions. Thus, where it is found that any of those exemptions apply to an establishment owned or operated by the employer the employees “employed by” that establishment of the employer are exempt from the minimum wage and overtime provisions of the Act without regard to whether such employees perform their activities inside or outside the establishment. Thus, such employees as collectors, repair and service men, outside salesmen, merchandise buyers, consumer survey and promotion workers, and delivery men actually employed by an exempt retail or service establishment are exempt from the minimum wage and overtime provisions of the Act although they may perform the work of the establishment away from the premises. As used in section 13 of the Act, the phrases “employee of” and “employed by” are synonymous.