Abstract: A system for the remote monitoring of vending machines and for automatically communicating conditions at the vending machines to a central computer complex is described. Each vending machine is provided with a microprocessor which monitors and stores data within that machine and transmits the data to the central computer complex either immediately or at scheduled call-in times. The distributed logic between the vending machine microprocessors and the central computer complex provides various alarm function signals and aids in inventory control and efficient route planning for the supply and maintenance of the machines. In a preferred embodiment the data is transmitted between the central computer complex and each vending machine over telephone lines.

Abstract: A card reader for reading data cards of the type having columns of machine-readable information thereon and transmitting data outputs representative of this information to an interface, includes a read station for sensing the information in each column and generating corresponding data outputs. A latching circuit receives data outputs from the sensing means and transmits the data outputs to the interface responsive to a strobing signal. A timing wheel is employed to detect the velocity of the cards during transport through the read station to provide an output proportional to velocity. A train of pulses is generated for each column responsive to the velocity output, and the period of the pulse train is adjusted to compensate for increases or decreases in the velocity of the card through the read station, by employing a phase-locked loop circuit.