Mobile phone maker Sendo has filed a lawsuit against Microsoft alleging the attempted theft of technical expertise and proprietary technology, adding to the intrigue surrounding its recently-terminated relationship with the software giant.
A Sendo spokeswoman said that the company believes "the allegations are serious and substantial", but declined to give further details.
The lawsuit was filed in US federal court in Texarkana, Texas on Friday. Sendo is based in the UK, but its North American headquarters are in Dallas, and its as-yet-unreleased Z100 smartphone is powered by OMAP technology from Texas Instruments, also based in Texas.
In early November, Sendo cancelled the launch of the Z100 shortly before it was to make its debut as one of the first smartphones powered by Microsoft software. At the time, Sendo declined to give a reason for the decision, but quickly allied itself with Symbian, one of Microsoft's principal competitors in the nascent market for smartphone operating systems.
Microsoft declined to comment on the lawsuit, but has said in the past, when rumours of a legal complaint by Sendo emerged, that any claims were without merit.
The relationship between Sendo and Microsoft, a minority stakeholder, has never been completely free of conflict. Sendo freely admitted that the Windows for Smartphones platform had its flaws. The company made sure that its own Windows-based handset included Java, a technology that directly competes with Microsoft's own platform.
Sendo's management privately complained that value-added features Sendo had introduced into the Z100 had later appeared in rival smartphone handsets Microsoft was involved in, according to Reuters.
Sendo planned to sell more than 1 million smartphones in its first year, at a cost of around 350 euros (£235). The company's alliance with Symbian and Nokia will mean it can relaunch the handset with different software, but the process of changing the phone is expected to take about a year.
Only one other handset is on sale now using Microsoft's software, the SPV, manufactured by Taiwan's HTC for France Telecom-owned Orange. Other handset makers such as Samsung have agreed to make Microsoft-based phones.