(cable television) standards, as does the Society of Cable Telecommunication Engineers. Another important group is the Alliance for Telecommunication Industry Solutions. This INTRODUCTORY CONCEPTS group prepares standards dealing with the North American digital network. Bellcore (Bell Communications Research, now called Telcordia) is an excellent source for standards with a North American flavor. These standards were especially developed for the Regional Bell Operating Companies (RBOCs). There are also a number of Forums. A forum, in this context, is a group of manufacturers and users that band together to formulate standards. For example, there is the Frame Relay Forum, the ATM Forum, and SO on. Often these ad hoc industrial standards are adopted by CCITT, ANSI, and the ISO, among others. 1.6 THE ORGANIZATION OF THE PSTN IN THE UNITED STATES Prior to 1984, the PSTN in the United States consisted of the Bell System (a part of AT&T) and a number of independent telephone companies such as GTE. A U.S. federal court considered the Bell System/AT&T a monopoly and forced it to divest its inter- ests. As part of the divestiture, the Modification of Final Judgment (MFJ) called for the sep- aration of exchange and interexchange telecommunications functions. Exchange services are provided by RBOCs (Regional Bell Operating Companies); interexchange services are provided by other than RBOC entities. What this means is that local telephone service may be provided by the RBOCs and long-distance (interexchange) services by non-RBOC entities such as AT&T, Sprint, MCI, and WorldCom. New service territories called Local Access and Transport Areas (LATAs), also referred to as service areas by some RBOCs, were created in response to the MFJ exchange-area requirements. LATAs serve the following two basic purposes: They provide a method for delineating the area within which the RBOCs may offer services. They provided a basis for determining how the assets of the former Bell System were to be divided between the RBOCs and AT&T at dives