Structured wiring is a rationalised type of data wiring, usable for many different purposes.
To get an idea what it is, imagine a primitive manual telephone exchange. Refer to the diagram. The specification of the wiring that's used is much superior to ordinary telephone wire. The question of which wire goes to which pin, and in particular which pin is paired with which, is laid down in a standard. To make use of a socket, for a particular purpose, you request us to connect it to the data service that you want.