Apparatus and method for receiving and decoding the bursts of line current activity produced by rotary dial action in dialing a sequence of digits. In accordance with the apparatus of the present invention, a rotary dial pulse receiver counts the number of bursts of line current activity produced by...http://www.google.co.uk/patents/US4944001?utm_source=gb-gplus-sharePatent US4944001 - Rotary dial pulse receiver
