US Patent 7283823 Handoff between cellular and enterprise wireless networks

A mobile station includes a first wireless interface that can couple to a first wireless network, a second wireless interface that can couple to a second wireless network, and a controller. The controller can negotiate a first wireless link with the first wireless network using the first wireless interface and establish a communication session with a remote device using the first wireless link. The controller can also detect a session handoff trigger, negotiate a second wireless link with the second wireless network using the second wireless interface in response to the session handoff trigger, and invoke a private branch exchange feature to transfer the communication session from the first wireless link to the second wireless link.