Telephonic enquiry system

Claim 1

An improved telephone remote enquiry system of the type which automatically answers a telephone call from a dial type or push-button type telephone and thereafter responds to a code number signal transmitted over the telephone lines by the calling party, wherein the improvement comprises: multifrequency decoder means for detecting whether the code number signal is in the form multifrequency signals from a push button type telephone and for decoding any such multifrequency signals into a binary coded decimal output representative of the code number signal, dial pulse counter means for counting dial telephone produced pulses to generate a binary coded decimal output representative of the code number signal, mode selector means for determining whether the code number signal is in the form of dial pulses or multifrequency signals and for selecting the appropriate binary coded decimal output of either the multifrequency decoder means or the dial pulse counter means, system control means activated by the binary coded decimal output signal from the mode selector means for providing an audible response over the telephone lines to the calling party which is specific to the code number signal, and wherein the dial pulse counter means further includes dial pulse processing and counting means for detecting and counting dial pulse signals over noise pulses, the dial pulse processing and counting means including, first means for detecting the first leading pulse of a train by checking whether the next subsequent pulse occurs within a predetermined time period thereafter, second means for comparing the amplitudes of all subsequent pulses with a first fixed percentage of the amplitude of the immediately preceding pulse and qualifying as valid all such pulses whose amplitudes exceed the first fixed percentage, third means for restarting the first means if the amplitude of the next valid pulse occurs before the expiration of the predetermined time period following the receipt of the first leading pulse, the third means repeating this procedure in iterative fashion until the first leading pulse is finally determined by the receipt of a subsequently occurring valid pulse at the end of the predetermined time period with no intervening valid pulses, and fourth means for counting pairs of valid pulses which occur with predetermined timed relationships with respect to the finally determined leading pulse and for generating an output signal representative of the count.