Abstract: A telecommunication system including a rotary dial subscriber set for transmitting sequences of dial pulses to a telephone central office over at least two conductors is disclosed. In response to a first set of dialed digits, the central office establishes a DC conductive path between the subscriber set and a DC blocking trunk circuit. A central office scan arrangement is connected to the communication path to determine the conduction state between the conductors of the communication path in order to maintain or remove the communication path. The system also includes a dial pulse detector which detects and counts dial pulses in each sequence of dial pulses transmitted from the subscriber set. In response to the first dial pulse of each sequence, the dial pulse detector generates signals which are utilized to inhibit the central office scanner from detecting further dial pulses.