1.1 This International Standard includes rules for identifying and marking ports in pneumatic directional control valves. These ports are the main flow connections, control connections and pilot supply connections. 1.2 This International Standard includes rules for identifying and marking electrical leads for solenoids. It is not applicable to internal electrical connections across manifold sections, such as connections to bus systems. 1.3 This International Standard includes rules for identifying and marking control mechanisms of directional control valves. 1.4 This International Standard includes rules for identifying and marking ports and/or flow path directions in filters, regulators, lubricators, non-return (check) valves, flow control valves and other ancillary devices. 1.5 This International Standard does not include rules for identifying and marking ports on proportional pneumatic valves, air logic valves, cylinders, air motors, semi-rotary actuators, air compressors, air dryers or other devices not specifically described in this International Standard.