They create systems for automobiles, robotics, aircraft, or power generation for an entire city. Engineers are required to be licensed, which can be achieved by completing a bachelor's or master's degree in electrical engineering and taking an examination.
In network addressing, the host address, or the host ID portion of an IP address, is the portion of the address used to identify hosts (any device requiring a Network Interface Card, such as a PC or networked printer) on the network.
Circuit ID. A circuit ID is a company-specific identifier assigned to a data or voice network between two locations, usually local telephone exchanges. The circuit is then leased to a customer by that ID.