Microsoft has been rumored to be working on a "Surface Phone" for years now, with little concrete evidence that such a device actually exists. "But the latest Windows 10 Insider Preview has given new fuel for the speculative fire, it has a set of new Apis for cellular phones," reports Ars Technica. From the report: Windows has had integrated Support for cell modems since Windows 8, but this has been restricted to supporting data connections. Telephony -- dialing numbers, placing calls -- has always required either Windows Phone or Windows 10 Mobile. This has made the full Windows 10 unsuitable for a phone. That may be changing. Windows 10 build 17650 -- a preview of Redstone 5, the next Windows update after the delayed April update -- includes some telephony APIs. The new APIs cover support for a range of typical phone features: dialing numbers and contacts, blocking withheld numbers, support for Bluetooth headsets and spearphone mode, and so on and so forth. There also looks to be some kind of video-calling support, suggesting support for 3G or LTE video calling.

Read more of this story at Slashdot.