RI). BRI is channelized into three channels, two bearer or B channels at 64 Kbs, and one delta or data or D channel (16 Kbs) used for signaling and control purposes. PRI access is facilitated with T1 transmission facilities and is channelized into 23 to 64 Kbs B channels and 1 to 64 Kbs D channel. It should be emphasized that the previous explanation is purely in terms of technical capability. Leveraging the bandwidth into variable amounts and getting charged for it on a case-by-case, service-by- service basis is an entirely different matter. For example, ISDN-based Internet access never achieved large usage because the equipment used by ISPs and their users was limited to BRI rates-64 Kbs at best. And because the ISPs are not the telephone company and have no capability, such as a big digital circuit switch, and have no funds available to buy a big digital circuit switch and therefore no interest in competing with the telephone company, they only offer Internet access service. From the tele- phone company viewpoint, they simply are prevented from being in the data services-Internet access, or Internet service provider (ISP) business-by current FCC rules and legislation. The telephone company can only sell POTS, ISDN, or private line service. It cannot offer any type of switching other than these services. Some of the independent non-regional Bell operating telephone companies have purchased and operate ATM equipment, but basically they are quite limited in the service they can provide using these or other non-voice service, frame relay, and IP-based switching and routing systems. DSL access varies according to several factors, the main one of which is the distance between the subscriber premises equipment and nearest central office or wire center. Conceptually and technically, DSL access is intended to be capable of multiple service types such as voice and data. However, implementation reality has driven most service providers to offer only Internet access without any voice service initially. It remains to be se