Vending and recording apparatus

Claim 1

Vending and sales recording apparatus useable in multiroom transient housing, including hotels, comprising in combination: a power line; a plurality of vending machines energizable from said power line, each vending machine having a plurality of vending units, each vending unit being actuable on demand for dispensing items of goods or the like; means in each vending unit responsive to such dispensing for then providing pulses as a signal representing the cost of the item of goods dispensed by said vending unit, there being in a one of such vending machines plural ones of said means providing different signals representing different costs; a low frequency modulator means for each vending machine and connected to the vending units thereof, said low frequency modulator means including an audio-frequency source and means for modulating the output of said audio-frequency source with said pulse signal to produce a pulse modulated audio signal; a high frequency modulator means connected to said low frequency modulator means and including a carrier frequency source and means for modulating the output of said carrier frequency source with said pulse modulated audio signal to produce a modulated carrier signal; means coupling said modulated carrier signal to said power line; a central control unit having a receiver means coupled to said power line and including carrier frequency demodulating means for separating said audio frequencies from said carrier frequency and means for demodulating a selected one of said audio signals to provide a cost signal; a counter responsive to the cost signal output from a given receiver and audio demodulating means thereof for summing the cost of articles dispensed by a given vending machine as they are dispensed; vending machine enabling means for controlling energization of the vending machines.