Using an absolute positioning system to record the cars precise position is a contemporary feature that can be achieved with a variety of measuring systems. The heart of the Kollmorgen APS is an absolute positioning encoder that is fastened on the guide rail with a specially engineered stainless steel mechanism and is driven by a toothed belt tensed on the shaft and fastened on the car and counterweight. This world-class positioning system is linked to the microprocessor of the control system with a serial interface. The cars position is transmitted right down to the millimetre and when there is a power failure, the control system identifies the precise car position so that it is not necessary to run a reset trip. Its stop precision is 5 mm and using a toothed belt has the advantage of easy and error-free assembly over other measuring methods such as light waves or wires. The toothed belts used have specially stranded steel tension lanes and an atypical L-division for quiet slip-free belt run.