raised for them by others; and that those persons otherwise eligible under § 91.501(d) (7) may use their radio facilities in connection with the servicing of the equipment that uses the products delivered.

(c) Communications relating to any of the following shall not be transmitted by any station licensed in the Special Industrial Radio Service:

(1) Sales reports or the dispatching of salesmen;

(2) Payrolls, accounts, or inventory control;

(3) Any message relating to the retail delivery of any item or product, except where such retail delivery is specifically included in the eligibility provisions of this subpart; or

(4) Any message where the time element is not of immediate importance.

(d) Persons engaging in activities some of which are eligible under this subpart and some of which are not, and desiring to use radio in connection with both types should apply for authorization in the Business Radio Service. § 91.503 Station limitations.

(a) Mobile relay stations will not be authorized in the Special Industrial Radio Service within the continental limits of the United States, except when such sta

tions and all associated control and mobile stations are to be operated exciasively on frequencies above 450 Mcs: Provided, however, That this restriction shall not apply to the continued Sceneing of mobile relay systems authorized prior to November 1, 1955.

(b) [Reserved]

(c) Base or mobile stations being utilized in itinerant operations at various temporary locations and not associated with a permanent service ares will be authorized only on frequencies indicated for itinerant use or for general

use.

(28 PR. 14144, Dec. 21, 1963, as amended st 29 F.R. 18225, Dec. 23, 1964]

§ 91.504 Frequencies available.

(a) The frequencies or bands of frequencies available for assignment to stations in this Service are enumerated in the following table, together with the class of station(s) to which they are normally assigned. a general reference terminology, and the specific assignment limitations which are developed in paragraph (b) of this section. Special provisions relating to the availability and the assignment of certain frequencies above 152 Mc ́s in Hawaii, Puerto Rico and the Virgin Islands are contained in paragraph (c) of this section.