Licensed, professional two-way radio is on the verge of making the biggest leap forward since the invention of the transistor — the move from analog to digital. Digital radio offers many advantages over analog, including improved voice quality at greater range, better privacy, sophisticated call-control features, the ability to easily integrate with data systems, and more. We’re now at the beginning of what will quickly become a large-scale migration to digital radio in professional applications. At the same time, regulatory pressures combined with real-world operating needs are driving radio manufacturers and users to communicate more information in a given slice of RF spectrum — in other words, to increase “spectral efficiency.” Channels that historically carried a single call at a time are now being divided so they can carry two.