T-Mobile has announced the launch of its "Digits" program, coming May 31. Digits is a revamp of how T-Mobile phone numbers work, virtualizing customer numbers so they can work across multiple devices. It sounds a lot like Google Voice—rather than having a phone number tied to a single SIM card or a device, numbers are now account-based, and you can "log in" to your phone number on several devices.

T-Mobile says the new phone number system will work "across virtually all connected devices," allowing multiple phones, tablets, and PCs to get texts and calls. This means T-Mobile needs apps across all those platforms, with the press release citing "native seamless integration" in Samsung Android phones, Android and iOS apps, and a browser interface for PCs.

The new phone number system is free to all T-Mobile customers. Customers can also buy an extra phone number for $10 or by signing up to the $5-per-month "T-Mobile One Plus" package, which is a bundle of extra features like a mobile hotspot and in-flight Wi-Fi. Here, the "extra number" use case matches what Google Voice users have been doing for years: a personal and business number, or a number to give to online sales sites like Craigslist, or an easily dumpable number for your Tinder dates. Unlike Google Voice, the $10 fee means T-Mobile has no problem distributing a ton of phone numbers, and the mobile telco says you can access up to five lines from a single device.

T-Mobile also encourages assigning a single phone number to devices owned by multiple people. So you could have a single number ring everyone in a household, or businesses could have a customer service line ring everyone in customer service.

Digits is rolling out to every T-Mobile device on May 31.