Call-routing device

Claim 1

A telephone dialer for routing calls placed on a telephone system that includes a plurality of extension lines and a plurality of outside lines connected to facilities of common carriers and that further includes switching circuitry that makes connections between extension lines and between extension lines and outside lines, the switching circuitry being of the type that responds to a flashing signal from a called extension line by placing a calling extension line on hold and presenting a dial tone to the called extension line, that thereafter connects the called line to a third line designated by signals from the called line, and that thereafter connects the calling line to the third line in response to a subsequent removal of an off-hook signal from the called extension line, the telephone dialer comprising: A. a dialer port, adapted for connection to an associated extension line, for receiving signals from the extension line and transmitting signals thereover; B. a ring detector connected to monitor signals received over the dialer port and generate a call signal when the dialer port carries ringing signals caused by the placing of a call from a calling extension to the dialer; C. a termination circuit operable to place a loop termination across the dialer port and thereby send an off-hook signal to the switching circuitry, the termination circuit further being operable to remove the loop termination from the dialer port and thereby interrupt the off-hook signal; D. a control circuit connected to receive call signals from the ring detector, operate the termination circuit, and send and receive signals over the dialer port, the control circuit responding to call signals from the ring detector by operating the termination circuit to place a loop termination across the dialer port and by sending a dial tone to prompt a user at a calling extension to send dial signals that represent a destination code, the control circuit further detecting the dial signals from the calling extension and storing the destination code represented thereby, sending the flashing signal over the dialer port to cause the switching circuitry to put the calling extension on hold, selecting a common carrier over which to place the call dialed from the calling extension, sending signals necessary to place a call, over the selected common carrier, to the destination station indicated by the destination code, and operating the termination circuit to remove the termination loop from the dialer port so as to release the line connected to the destination station and cause the switching circuitry to connect that line to the calling extension line.