BlackBerry has filed a patent lawsuit (PDF) against internet telephony firm Avaya. The dispute marks a turning point for Blackberry, which pushed into the Android market last year but has been struggling.

In making its case that Avaya should pay royalties, BlackBerry’s focus is squarely on its rear-view mirror. The firm argues that it should be paid for its history of innovation going back nearly 20 years.

“BlackBerry revolutionized the mobile industry,” the company’s lawyers wrote in their complaint. “BlackBerry… has invented a broad array of new technologies that cover everything from enhanced security and cryptographic techniques, to mobile device user interfaces, to communication servers, and many other areas.”