FCC opened unlicensed spectrum for spread-spectrum devices

Radio spectrum regulation since Marconi's era ran on one principle: interference is prevented by exclusivity. The FCC assigned each licensee its own frequency and enforced against anyone who transmitted on someone else's, and getting a new use authorized meant a rulemaking process that could take years per applicant.

The bands the FCC could plausibly open quickly were the ones nobody wanted: the Industrial, Scientific and Medical (ISM) bands at 902-928, 2400-2483.5 and 5725-5850 MHz, reserved for microwave ovens and diathermy machines that radiate RF energy with no power limit at all — engineers who worked in the industry called them the "garbage bands." Granting exclusive licenses there was pointless, since no licensee could ever be protected from a microwave oven's own unlimited emissions; the FCC's own conventional tool, exclusivity, simply did not apply.

Opened unlicensed ISM bands to spread-spectrum devices, making the technology absorb interference so the FCC never had to arbitrate access.

No licensing meant no arbitration burden on the FCC.

No protection forced device makers to engineer for coexistence.

Competition among makers drove better interference tolerance.

Spread spectrum made uncoordinated use survivable.

When gatekeeping is too slow, open a low-value slice to all comers with no guarantees, and let competition force technical robustness.

Adoption was slow at first — the first equipment authorization under the new rule wasn't granted until 1988, four years later, to a Canadian firm, Telesystems SLW — but by the early 1990s, as the FCC widened the allowed bandwidth, a wireless LAN industry (Apple among the earliest entrants) had adapted its equipment to survive in what one 1994 industry paper called the bands' 'feral territory,' engineering around interference rather than waiting for a regulator to prevent it. 4 GHz ISM allocation Marcus had opened nine years earlier.