Fax tech is older than you think—first prototype hit in 1843 with Alexander Bain's "Electric Printing Telegraph" using pendulums and telegraph lines to transmit images.

The real engineering insight: a single fax is useless. Network effects kicked in when multiple units existed—2 faxes = utility, many faxes = critical infrastructure.

Military drove early adoption hard:
- 1890s: U.S. Army/Navy used it for fire control in coastal forts and naval ops, plus transmitting written orders during loud weapons tests where voice comms failed
- WWI: Germans faxed maps and artillery coordinates, even tested wireless fax from airplanes
- 1930s-40s: News orgs used it to transmit photos at scale

Key milestones:
- 1880s-1920s: Scanning phototelegraphy + wireless image transmission
- 1924: First color fax transmission over cable
- 1964: Xerox Magnafax Telecopier—6-minute document transmission over phone lines, the first "modern" fax

Fax became the backbone for legal/contract transmission because it was fast, verifiable, and had legal standing before email existed. Classic case of boring tech winning through reliability and network lock-in.