MCI turned a two-city private line permit into long-distance by adding a dial tone

In 1969 the FCC granted MCI Communications a narrow authorization: a private line connecting a customer's offices in St. Louis and Chicago, priced as a flat monthly alternative to AT&T's long-distance rates for that one fixed route.

MCI was a struggling startup that had barely turned a profit selling that one narrow point-to-point service. A direct application to the FCC for a general long-distance license would have meant years of hearings before a regulator with every institutional reason to protect AT&T's cross-subsidy system, and no obligation to move quickly on a request that threatened to unravel it.

Sold Execunet as a dial-up service on its existing private-line authorization, letting any subscriber reach any number, which the courts ruled was within its license.

The permit's text didn't specify who could originate calls or how many endpoints, leaving a gap.

Launching Execunet as a real product put the question before courts with customers already using it.

The D.C. Circuit ruled the text didn't forbid the broader use, forcing AT&T to interconnect.

Revenue jumped from under $1M to $95M, proving the market was waiting.

When a permission seems narrow, read its literal text for unstated limits; if none exist, build and sell the broader use before asking.

AT&T recognized the threat within months and filed a complaint with the FCC, which agreed and ordered MCI to shut Execunet down as an unauthorized long-distance service. S. C. Circuit found that nothing in MCI's actual FCC authorization forbade what Execunet did, ruling that the FCC had to let MCI compete for ordinary long-distance traffic; a follow-up 1978 ruling forced AT&T to interconnect its network with MCI's. MCI's revenue, under a million dollars combined through 1974, jumped to $7 million in 1975 and reached $95 million by 1979.