In an atypical move, Google has filed a patent infringement suit against BT's American operation and its VoIP services, charging them with treading on Google IP related to network communications.FOSS Patents says the filing means that Google CEO Larry Page will never again be able to say, "We've never sued anyone over patents."It's tit for tat. BT accused Google of infringing six of its mobile device patents in a 2011 suit that indicts Android, Gmail and Google Maps.Google claims, "We have always seen litigation as a last resort, and we work hard to avoid lawsuits. But BT has brought several meritless patent claims against Google and our customers