When our cable tester tests a cable, the circuit diagram is drawn on the screen (see example below). On-screen diagrams are surprisingly useful - even for large cables where the complexity of the wiring cannot be comprehended at a glance.
This is because common faults are instantly and obviously visable (e.g. forgetting to plug a socket in, wiring a socket the wrong way around, or even pressing the wrong push-button and hence executing the wrong test!). After the same type of cable has been tested several times, operators gain a mental picture of what the correct image looks like (and also what their common errors look like). Whilst Cable Doctor can produce instant, detailed error reports of all wiring errors, a high percentage of problems are solved very quickly - just by glancing at the screen diagram. In these instances, operators don't even need to look at the reports.