Abstract: In a plurality of logical device driver instances, each instance (201) representing a specific version (220) of the device driver, can be accessed by an embedded application (200) via a common interface (205). A logical device driver instance includes the common interface which includes a plurality of functions (206-209) linked to the embedded application. A logical device driver also includes a virtual function table (211) having pointers (212-215) that points from each of the plurality of functions of the common interface to a plurality of functions (221-224) of a specific version of the device driver among a plurality of versions of the device driver. The virtual function table is set up dynamically during run-time initialization of a logical device driver instance.

Abstract: A distributed processing system (100) includes a protocol server (101) that enables a plurality of clients (103-104) to share the use of one set of Signaling System 7 (SS7) links (99), that centralizes the link-termination circuitry (110) for use by the plurality of clients, and that provides access to upper layers (215-219) of the SS7 protocol stack (200) by distributing the processing of different layers of the stack between the protocol server and the clients. The protocol server terminates the lower layers (210-213) of the SS7 protocol, while each client terminates the upper layers of the SS7 protocol. Communication between the protocol server and the clients of information expressed in the upper layers of the SS7 protocol is effected via the TCP/IP protocol over a LAN (102).

Abstract: An automatically progressively-activated and reset "send-all-calls" (SAC) feature provides the following functionality. In response to receipt at a switching system of each call for a destination subscriber station that has the feature enabled, the system retrieves a stored specified period of time for which a call directed to the station is allowed to go unanswered at the station, and then shortens the stored specified period, thereby progressively hastening activation of SAC for a subsequent call. If the retrieved period is of nonzero duration, the switching system directs the received call to the destination station. If the retrieved period is of zero duration, or if the directed received call goes unanswered at the destination station for the duration of the retrieved period, the switching system redirects the call to a call-coverage facility in the manner of a standard SAC feature.