Figure 1-1.System subdivision.
As naval electronics has grown in capability and complexity, an orderly plan of equipment
designations has been adopted. The largest designator, system, describes equipment that work together for
a specific function. For example, the radar system of a ship includes every item of electronics equipment
used in or with a radar on board that ship. The smallest designator, part, describes one single piece, such
as a bolt or a resistor.
A SYSTEM is a combination of sets, units, assemblies, subassemblies, and parts joined together to
perform a specific operational function or several functions. Examples are communications systems, radar
systems, or navigation systems. You will find the majority of troubleshooting done in the Navy is system
oriented. Figure 1-2 is a pictorial view of a typical communications system containing the components
necessary for transmission and reception of voice, telegraphy, and teletypewriter signals. Figure 1-3 is a
block diagram of the same communications system with the arrows showing the direction of signal flow.