art include, but are not limited to, the duties specified in § 1926.1402(c), § 1926.1402(e) and § 1926.1424(b). (f) Where provisions of this standard direct an operator, crewmember, or other employee to take certain actions, the employer must establish, effectively1926.1420 Signals--radio, telephone or other electronic transmission of signals. 1926.1421 Signals--voice signals-- addi