Abstract: A time recorder receives bar coded time cards, punches time data on the cards and stores the time data in memory. Each card has a bar code at each end corresponding to the same value. For each pay period, a unique bar code and the card on which it is printed are assigned to each employee during an initialization process. A card is inserted upside down into the time recorder for each employee and the bar code is read by the system and assigned to an employee. At the same time, employee information is printed on the card.

Abstract: A readout circuit for determining the displacement of a magnet relative to a fixed reference point is disclosed. The relative displacement is determined by measuring the time interval required for a stress wave created in a magneto-strictive probe adjacent to the magnet to travel to the reference point. The readout circuit includes a counter means for counting at a predetermined rate. In order to determine the displacement of the magnet using the readout circuit, a pulse signal is generated in the probe causing a stress wave to be created in the probe at the location of the magnet. The counter means of the circuit is then activated in timed relation to the generation of the pulse signal. A means for detecting the arrival of the stress wave at the reference point and for stopping the counter means when the wave is detected is also provided in the readout circuit. By measuring the travel time for the stress wave with the readout circuit, the displacement of the magnet is determined.