Direct digital control (DDC) ordinarily refers to executing control of devices using electronic digital technology to the point of the controlled device. Today, DDC for HVAC systems is usually provided by a networked set of sensors and controllers that are connected to actuators moving controlled mechanical devices such as valves, dampers, fans, and pumps by sending them voltage signals. Access to data on this network often is available for viewing on field panels with integrated displays or by one or more building automation system (BAS) computers.