Private Branch Exchange (PBX) telephone systems are used in many businesses to enable workers to make and receive calls from the Public Switched Telephone Network (PSTN) and other PBX phones within the enterprise. PBX systems also provide a host of telephonic services to the enterprise workers including call forwarding, transferring, conferencing, voice mail, personalized greetings, and the like.
In many cases, an enterprise worker's phone resides on the desktop in immediate proximity to the worker's personal computer. The personal computer may provide tools for word processing, viewgraph editing, email, and web browsing, as well as other communications tools such as instant messaging, buddy lists, presence, video, and other tools for collaboration. Instant messaging allows people with network access to send text messages and other media to other individuals listed in a buddy or contact list. An instant text message is sent in near-real time to a contact where it is then displayed in a graphical user interface window within the context of an on-going text-based conversation. In addition to text messages, instant messaging may also be used within chat sessions and custom chat rooms where friends or co-workers can interact and share media. Some instant messaging applications are also enabled with a presence protocol used by a one person to determine whether a buddy or contact is “present” online and to subscribe to changes in the presence state or information.
Despite the prevalence of PBX phones and communications-enabled personal computers in the enterprise, there is an absence of sufficient integration between these two types of communication systems. For example, an enterprise worker's instant messaging application may be aware of the worker's online presence but is oblivious to the worker's telephonic presence, i.e. buddies do not know that a worker is occupied on his PBX phone. Or, as a second example, although a worker sets up a voice session to another worker by dialing a PBX extension, an entirely separate process must be followed to setup a session for exchanging a document. Therefore, there is a need for a solution that integrates the PBX system and communications applications on enterprise workers' computers to provide greater interoperability, simplified PBX control, and enhanced sharing and collaboration.