Abstract: A method and apparatus for automatically establishing a data connection includes a telephone line interface circuit coupled to a subscriber telephone line, and a modulator and demodulator circuit coupled to the telephone line interface circuit. A control circuit is coupled to the modulator and demodulator circuit and conditions the modulator and demodulator circuit to establish a connection to the subscriber telephone line and comprises circuitry to determine whether a central office to which the subscriber telephone line is connected is a tone-dial central office or a pulse-dial-only central office, whether a dialing prefix is necessary to access the subscriber telephone line, and whether the call waiting feature is activated on the subscriber telephone line.