As the coil and a vacuum tube made possible an early telephone network, revolution of wireless technologies began only after cheap microprocessors and digital switches became available. The Bell System, producers of the best wire telephone system in the world, passed to wireless technologies indecisively and sometimes with indifference. That made AT&T, it had to work reliably with other part of their network, and it had to make economic sense. Something inconceivable for them with their limited (because of small number of frequencies available at that time) number of clients. Availability of frequency in turn was operated by the Federal Commission of Communication, whose norms and stagnancy made the most significant obstacles to development of a radio telephony, especially with cellular radio, detaining this technology in America it is possible for 10 years.
Europeans saw things in other light. No new telephone system could unite their existing services working at so many frequencies. They decided to begin instead with new technology on new radio frequency range. Structured on cellular type, but completely digital, new service had to include all best thoughts of that time. They created the new wireless standard according to requirements for wire ISDN, hoping to make wireless analog. New service was called GSM.