29 C.F.R. § 541.502
An outside sales employee must be customarily and regularly engaged "away from the employer's place or places of business." The outside sales employee is an employee who makes sales at the customer's place of business or, if selling door-to-door, at the customer's home. Outside sales does not include sales made by mail, telephone or the Internet unless such contact is used merely as an adjunct to personal calls. Thus, any fixed site, whether home or office, used by a salesperson as a headquarters or for telephonic solicitation of sales is considered one of the employer's places of business, even though the employer is not in any formal sense the owner or tenant of the property. However, an outside sales employee does not lose the exemption by displaying samples in hotel sample rooms during trips from city to city; these sample rooms should not be considered as the employer's places of business. Similarly, an outside sales employee does not lose the exemption by displaying the employer's products at a trade show. If selling actually occurs, rather than just sales promotion, trade shows of short duration ( i.e., one or two weeks) should not be considered as the employer's place of business.
29 C.F.R. §541.502