Abstract: A method of using co-routines to implement a function-like interface between a BASIC program and the points in the system where SIP and SDP data (for example) are to be modified. This co-routine interface is intuitive from the end-user's perspective, and both real-time efficient and flexible from the system designer's perspective, and is applied to provide user-customized SIP and SDP modifications in an easy-to-use way that gives the end-user great flexibility while protecting the system from the undesirable side-effects that could result from a tightly coupled co-routine interface.

Abstract: An exploitation of the proper classification of conventional call processing states into categories, each category corresponding to one of the call states of the SIP finite-state machine (FSM), yields simplified design, implementation, and operation of heterogeneous call processing. A separate FSM for the SIP-categorized call states running in parallel with a conventional port event processing (PEP) FSM, implements a VoIP Local Call Controller by passing events between the SIP-type FSM and the PEP FSM only at the points where a transition between SIP categories occurs. The SIP FSM does not require notification of PEP FSM transitions not affecting the SIP call state. For this reason, none of the code associated with the transitions between PEP FSM states within the same major state category requires any modification. Consequently the integration of VoIP and PEP call processing can be done more simply, and at dramatically-reduced cost in software development, support, and maintenance.

Abstract: A method of using co-routines to implement a function-like interface between a BASIC program and the points in the system where SIP and SDP data (for example) are to be modified. This co-routine interface is intuitive from the end-user's perspective, and both real-time efficient and flexible from the system designer's perspective, and is applied to provide user-customized SIP and SDP modifications in an easy-to-use way that gives the end-user great flexibility while protecting the system from the undesirable side-effects that could result from a tightly coupled co-routine interface.

Abstract: A key telephone system which provides both key and private branch exchange (PBX) operational modes utilizes a plurality of digital telephone station sets which communicate with line circuits connected to a time division multiplex (TDM) telephone switching system. A single pair of leads (tip and ring) connect each station set to the line circuits. The TDM switching system has a processor with an operating system which carries out the processes which provide for the selection of key and PBX features. The TDM switching system also provides access to trunk lines which connect the telephone station sets via the TDM switching system to other switching systems, such as the central office of the public utility telephone company. In the station sets and in the line circuits, there are provided channels for signalling data and for PCM data. The PCM data may be voice, codes, or digital data.

Abstract: A communications switching system is controlled as a peripheral device to a general purpose digital host computer or other host device. The switching system has a plurality of ports for telephone lines and/or trunks and makes connections to the ports. The host computer is programmable at high level to obtain customized switching applications. The switching processes are carried out in the switching system under control of high level commands. The commands are formatted to identify the command functions and the ports at which the switching and control actions are to be carried out. These ports may be provided by separate modular switching units, each having processors for carrying out the switching functions at the designated ports and for distributing the commands in accordance with the command format to the designated port regardless of which of the modular switching units has the port.