Improved data transmission via a public switched telephone network

In a communications system comprising local communication lines, a services control point comprising a database for storing call processing data, a plurality of interconnected central office switching systems each connecting to a plurality of said local communication lines and responding to a service request on a connected local communication line to selectively provide a communication connection for a requesting line, and a signaling communication system interconnecting the central office switching systems and connecting the central office switching systems to the services control point, a method of completing a call comprising the steps of:

• receiving at an originating one of the central office switching systems via the requesting line an address for a message to be transmitted to a called party having a data terminal and a telephone, the address and message being generated at an originating facility and the address comprising an NPA-XXX-XXXX address of the called party and an added data set, said added data set being characteristic of a format of the message to be transmitted;
• transmitting the address from the originating central office switching system to a destination central office switching system serving the called party via the signaling communication system;
• outputting to the services control point via the signaling communications systems a query message from the destination central office switching system in response to the received address, the query message including said NPA-XXX-XXXX address and said added data set;
• accessing call processing data corresponding to the called party from the database of said services control point to formulate a connecting message in response to said added data set;
• sending a connecting message, generated in response to the accessing step, from the services control point to said destination central office switching system;
• and
• selectively establishing a communication link to a device other than said telephone for the requesting line through said destination central office switching system, in response to said connecting message, to enable the communication of said message to be transmitted.