The load source is the service object of the wiring harness, usually referring to the user equipment; Broadly speaking, the higher-level device is the load source of the next-level device. In telephone communication, the load source is also called the call source, and the number of service devices contained in the harness is called the harness capacity, and Figure 1 is a schematic diagram of the harness. The harness has a capacity of V and it serves N load sources. Any load source that places a call can occupy an idle service device in the harness.
