ilable on the PRI trunk, one or more are allocated to the station. Using the term station, we include both desktop video and data conferencing systems and group-systems. Issues Related to ISDN When the first set of ISDN standards was ratified in 1984, the CCITT (now the ITU- T), intended that it provide a migration path to move the historically analog PSTN to an end-to-end digital system. While the ITU-T was busy planning an evolution, customers were envisioning an immediate revolution to digital service. This did not account for the cost of upgrading a carrier networks for ISDN. The carriers that did deploy ISDN in the 1980s found inadequate demand for high-bandwidth digital service. ISDN, it was said, should stand for "innovation subscribers do not need." A decade after ISDN's introduction, several killer applications almost simultaneously emerged. Remote LAN access, telecommuting, Internet access, and low-bandwidth video communication proved that the CCITT had been right-and visionary in their thinking. The problem today is this: ISDN deployment is by no means seamless. In the present competitive environment, telephone companies face revenue pressures; budgets are much tighter as a result. Customer demand can lead to upgrades or work-arounds (back-hauling from an ISDN-capable CO, for instance), but implementation still takes time. Even when ISDN is available, its clear channel capabilities may not extend beyond the LEC's regional boundaries. This is due to an oversight in the original CCITT specification. ISDN defines two interfaces, the network-to-user (N-interface) and the user-to-user (U-interface). It does not now, nor will it ever, define a network-to- network interface. This means that extending ISDN's clear-channel capabilities between carrier's networks requires negotiated agreements and special engineering. When the LECs and IXCs work cooperatively, ISDN can be arranged to offer end-to- end digital service on a clear-channel (64 Kbps) basis. The component that makes ISDN capable of offering end-to-end