30 the combined tone is then applied to the input of and gate 70 to be gated by the interrupt circuitry as noted previously the interrupt circuitry consists of a d type flip flop 41 whose inputs c and d are connected to the 440 hz and 480 hz signal leads the operation of the flip flop in response to this combination of inputs would produce on the q output a 34 true 34 condition at the rate of 40 pulses per second or 2 400 pulses per minute this output signal is then applied to frequency divider 42 which divides by 20 producing an output of two pulses per second or 120 impulses per minute as shown in the accompanying drawing this 120 impulse per minute output is also strapped to and gate 70 which therefore provides the summed output of the 480 hz and 620 hz signals at a rate of 120 times per minute to the low pass filter 80 low pass filter 80 and amplifier 90 operate in the manner described above in connection with the description of low pass filter 50 and amplifier 60 to provide the desired reorder tone to the telephone central office equipment it should be.