Patent US 3,943,289

A prerecorded message is supplied to a plurality of telephone subscriber numbers automatically called in sequence from a local station. Upon placing the call to the first number, another second number is established by changing the first called number by a predetermined increment. In response to the first called number being reached, the prerecorded message is coupled to a telephone line at the local station. In response to the call being either completed or the elapse of a predetermined time during which it is expected that the called subscriber should answer the phone, a signal is derived to indicate that operations for the first party have been terminated. In response to the termination signal, the telephone is repeatedly hung up and picked up automatically until the prerecorded message has been completed and a dial tone has been detected, at which time the second number is called. The device is activated repeatedly in this manner. Counters are provided to sense the number of completed calls, the number of calls in which the called subscriber hangs up prior to the end of the prerecorded message and the number of called subscribers who cannot be reached.