al office, enabling its subscriber to get a local phone number from a distant city. FX numbers are useful both for avoiding outgoing toll costs and for providing an inbound virtual local presence in the targeted city. FX circuits, it should be noted, are said to have both an "open" end (the central office) and a "closed" end (the customer site). MCI, in the mid-1970s, created an innovative service that made FX-like service more affordable than AT&T's version, at least to smaller users. It offered measured-use shared FX. This allowed its intercity bandwidth to be shared by multiple FX customers, who would pay for their FX numbers on a minute-of- use basis. So a customer could have a closed end connection into MCI's switch- ing system, and the open end would be a distant Bell central office. The SCCs were subject to strict tariff requirements in those days, and the FCC accepted this tariff. Having tariffed an FX service with a switched open end, MCI also filed a tariff for FX service with a switched closed end. A group of customers could thus access an FX service by dialing in to it via a local number, in effect making both ends open. This was perhaps more than a small stretch in the definition of FX, but the SCCs were, after all, expected to be innovators. The real punch line occurred when MCI allowed customers to dial in to one open end, enter a touch-tone authorization code, and then select a destination number -the other open end-that could be a local call from any location served by the net- work. MCI called this service Execunet. Customers were quick to recognize it as a competitor to AT&T's WATS and MTS. Alas, SO were AT&T and the FCC. They quickly called foul. MCI pointed out that the FCC had indeed approved the tariffs from which Execunet was built-the FCC simply had not realized it at the time [18]! The FCC, per- haps not amused, froze Execunet's growth; AT&T was allowed to stop connect- ing new local lines to MCI's network, though it was prohibited from shutting off service entirely while the issue was l