A system and method for establishing a high speed, substantially constant circuit based data connection over a conventional telephone line is provided. The circuit based connection is non-switched, thereby eliminating the need to establish a connection through a dial-up process. The circuit based connection is established between a user's terminal device and a digitizer, such as a basic rate interface transmission exchange card. The user's terminal device may be a modified version of a conventional integrated services digital connection modem. A user's computer, telephone, or other device may be connected to the user's terminal device to access an external network. The connection established in accordance with the present invention can transmit data at a rate far exceeding that of traditional dial-up connections.