Abstract: A telecommunications system includes a telephone routing system; and a presence database manager unit operably coupled to the routing system and adapted to maintain one or more watcher lists of registered users. The routing system is adapted to receive phone calls and provide an indication to the presence database manager unit whether the phone calls originate from registered users. The presence database manager unit is adapted to determine if such a user has a watcher list and transmit an indication to parties associated with the watcher list that said user is present.

Abstract: An Accessing Busy Resources service is adapted to receive subscription requests from clients for notification of when a busy resource is free, and to monitor network resources to determine if they are free. Upon notification, the Accessing Busy Resources service de-subscribes the client. The network client devices include Access Request units which make requests to access services and receive notification when the services are available.

Abstract: A telecommunications system according to an embodiment of the present invention includes a packet network; a first plurality of network clients compatible with a first voice protocol of the network; a second plurality of network clients partially compatible with the first voice protocol; a third plurality of network clients compatible with a second voice protocol; a gatekeeper adapted to provide call control for the first plurality of network clients; a feature proxy adapted to receive registrations of the first plurality, the second plurality, and the third plurality of endpoints, and map such registrations to registrations with the gatekeeper and provide feature processing for the first, second, and third plurality of endpoints.

Abstract: A telecommunications system includes a telephone routing system; and a presence database manager unit operably coupled to the routing system and adapted to maintain one or more watcher lists of registered users. The routing system is adapted to receive phone calls and provide an indication to the presence database manager unit whether the phone calls originate from registered users. The presence database manager unit is adapted to determine if such a user has a watcher list and transmit an indication to parties associated with the watcher list that said user is present.

Abstract: An Accessing Busy Resources service is adapted to receive subscription requests from clients for notification of when a busy resource is free, and to monitor network resources to determine if they are free. Upon notification, the Accessing Busy Resources service de-subscribes the client. The network client devices include Access Request units which make requests to access services and receive notification when the services are available.

Abstract: A method and system for supporting private branch exchange features over a public switched network is provided. The proprietary private branch exchange call and feature control information is separated into standard ISDN public network protocol elements and proprietary ISDN protocol elements. The interface between the originating private branch exchange and the public switched network inserts the proprietary protocol elements into a UUS service data packet for transparently transmission to the destination private branch exchange. Thus, the proprietary private branch exchange feature control information can be recovered and utilized by the destination private branch exchange, thus permitting PBX-PBX feature transparency through a switched public ISDN network.