Section 90.465 - Control of systems of communication(a) Depending on design considerations, control of a system of communication may be exercised in varying ways. In single frequency simplex, base/mobile operations, control may be exercised by the control operator at the fixed control point. In mobile relay systems, where there is an associated control point or control station, control may be exercised by the operator at the control point or control station. In mobile-only systems, control may be exercised by the mobile operator. In communication systems involving multiple base stations or fixed relays control of the system may result from a combination of factors and considerations, including control by a fixed control point operator at some point within the system of communication or control by the mobile station operator of the licensee.(b) In internal systems, as defined in § 90.7 , control may be maintained by conforming the system to the requirements of §§ 90.471 through 90.475 .(c) In interconnected systems, as defined in § 90.7 , control may be maintained by conforming operation and system design to that permitted in §§ 90.477 through 90.483 .43 FR 54791, Nov. 22, 1978, as amended at 54 FR 39740, Sept. 28, 1989; 72 FR 35199 , June 27, 2007