A global wireless system for Android mobile devices from Google that supports Wi-Fi calling. Users seamlessly switch phone and data service between Wi-Fi hotspots and cellular. Introduced in 2015 and initially offered via invite-only, the Nexus 5x, 6 and 6p were the first phones to support Fi, which can be purchased directly from Google. Fi piggybacks over the Sprint and T-Mobile cellular networks along with more than a million free Wi-Fi hotspots that are automatically used.A Cloud-Based Phone NumberSubscribers are given a phone number that can also be used to make phone calls and send text messages from their tablets and computers via Wi-Fi or Ethernet.Fi Basics - USD $20 per MonthWith no annual contract, the Basic plan provides unlimited domestic talk, low international rates in 120 countries and unlimited international texting. Each gigabyte of encrypted data is an additional $10/month, and unused bytes are credited to next month's bill. Family sharing plans were not initially offered. See Google Fiber.