V.90 ended the 56k modem war with one ITU standard both camps could sell

In 1997, 56k modems came in two incompatible flavors: K56flex, from Rockwell and Lucent, and x2, from 3Com. Consumers had to choose an ISP that supported the same chipset as their modem, splitting the young market.

The International Telecommunication Union's Study Group 16 worked through 1997 and unveiled V.90 (draft name V.PCM) at a Geneva meeting in February 1998. It specified up to 56 kbps downstream and 33.6 kbps upstream, subsuming both proprietary schemes.

Vendors rallied immediately: Hayes, Cisco and Ascend formed an interoperability working group, 3Com pledged support, and makers of K56flex and x2 modems offered free V.90 upgrades. The standard was ratified by September 1998, and the modem wars were over.

Merge the rivals into one standard

One standard removed the modem-vs-ISP brand matching gamble.

Upgrade paths protected existing K56flex and x2 hardware.

Vendor pledges created instant market-wide interoperability.

A neutral standards body ended the proprietary standoff.

When two incompatible technologies split a market, neither wins until a neutral body merges them; a single standard converts a customer's brand-matching burden into a buying decision.

V.90 became the last great modem standard before broadband; users upgraded in place, ISPs deployed V.90 equipment, and the two rival camps' chipsets converged on one specification.