The vendors aren't saying whether the arrangement applies to Linux software used by Alpine.
The deal, disclosed Monday, expands an existing relationship between Microsoft and Alpine and will cover technologies used in in-car electronics such as sound systems and navigation devices.
Alpine already offers a number of products, including global positioning systems, that run atop a version of Microsoft's Windows operating system designed for vehicular use.
Full financial terms of the deal were not disclosed, though Microsoft said it will receive net payments from Alpine as part of the arrangement.
The statement has raised speculation that Microsoft may be charging Alpine for its use of the Linux operating system in some of its products. Alpine is a founding member of an industry group known as Emblix that promotes the use of Embedded Linux in consumer products.
Microsoft claims that Linux, an open source software project that's used alike by home PC enthusiasts and multinational corporations, infringes on 42 of its patents. Of late, the company has launched an enforcement campaign under which it's been attempting to collect royalties from vendors that use Linux commercially.
To date, Microsoft has reached Linux accords with Samsung, Novell, LG Electronics, and Linux distributor Xandros -- among others. Last year, Microsoft CEO Steve Ballmer said his company also expects payment from computer users who run a version of Linux distributed by Red Hat.
"People [who] use Red Hat, at least with respect to our intellectual property, in a sense have an obligation to eventually compensate us," Ballmer said at a company event in London in October.
For its part, the Linux camp has fiercely denied that the operating system violates any commercial patents or copyrights. Microsoft, to date, has refused to specify exactly which patents it believes Linux violates.