The concept itself is all about convenience — a way to get online in several countries without contracts and SIM swapping — but how has Microsoft got into a position to offer this data service? Well, a company called Transatel left us a big flat clue earlier this week when it announced it had been chosen by Microsoft to facilitate it. Transatel is something of an international mobile virtual network operator that piggybacks on the cellular infrastructure of provider partners around the world. The company’s “SIM 901 solution” plays nice with 3G/4G networks regardless of geography, and it’s undoubtedly this that’ll be rebranded as the Microsoft SIM. Currently, Transatel has agreements in 38 countries, but come January 15th it’ll operate in a total of 50, including the US, UK, Mexico, India, a few Asian markets and much of Europe. Giving the timing of the expansion, perhaps it’s an indication of when Microsoft intends to launch its data service in earnest.

Microsoft isn’t the only tech giant to take on the role of middleman, of course. Apple bundles its own carrier-agnostic SIM with cellular iPad models, allowing users to pick data plans from a few mobile network partners. It’s unclear whether Microsoft’s deal with Transatel will give users a choice of regional providers or a single rate they have to like or lump. Either way, it’s an interesting move from a company that primarily concerns itself with software and hardware. Microsoft told us it has nothing more to share beyond the information that’s publicly available right now, but no doubt we’ll hear the ins and outs soon enough.