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: Conveying Push-To-Talk and Push-To-Signal (PTT/PTS) information over an IP network through signaling bits defined in and propagated with the Real-Time Protocol (RTP) stream allows the PTT/PTS information to remain synchronized with the voice packets of the stream. The maintenance of synchronization of PTT/PTS signals and voice packets eliminates problems arising from failure of synchronization between the two classes of packets, notably the “shoot/don't shoot” problem. The signaling bits employed were formerly used to convey legacy network information, but are no longer in active use in the Voice-over-IP (VoIP) realm, since VoIP provides alternative pathways for their information.

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 TDM (Time Division Multiplexed) telephony switching system which provides expanded switching capacity without change in the physical form factor of the system or of the design of the circuits which provide TDM multiplexed digital signals (the port and service circuits). Additional ports and service circuits are provided in the same number of time slots per frame as existed before system expansion thereby providing additional ports and/or service circuits which can be interconnected without significantly affecting the cost of the system. Expansion is achieved by multiplexing the digital signals and transmitting them at a higher rate on existing send highways of the system. The time slot interchange is expanded by providing a memory with additional locations for each group of additional circuits.

Abstract: A time division multiplex switching system converts call formats and signalling protocols so that calls can be interchanged between circuits originating in different networks thereby providing a gateway for telephone transmissions originating from sources (e.g., foreign countries) having differences in transmission (signal attenuation characteristics and companding laws) and signalling and numbering plans or protocols. This switching system is characterized by a processor which is programmed to identify the circuits requiring interconnection and to process signalling messages in accordance with the signalling systems and formats used in the circuits, while translating the signalling messages into common, protocol independent signaling messages which are used for establishing time division multiplex connections in a time slot interchange which is connected to the circuits via PCM highways and for exchanging signalling information (e.g.

Abstract: A digital private automatic branch exchange provides a plurality of ports which may comprise line trunks or operator circuits, the ports being grouped with each group being controlled by an individual microprocessor circuit which performs all real time control over the ports. Voice communication between ports is effected by time division multiplex in connection with a digital switch system forming part of a common control which is controlled by a central processing unit responsive to the microprocessors in each port group for assigning time slots to each interconnection channel. Isolation between the central processing unit and the rest of the system is provided by a peripheral bus to which the common control units and port groups are connected, which peripheral bus is connected to the CPU bus by way of an interface circuit, permitting the system to operate with various types of central processing units without redesign of the peripheral units.

Abstract: A system for generating calls in order to test telephone switching systems by simulating traffic loads has line interface circuits which send calls independently and in selected sequence on any number of a group of lines into the telephone switching system under test. Lines of the telephone switching system which are supposed to be called are terminated by the interface and outputs representing the successful completion or failure to complete calls are obtained. Commands for controlling the generation and termination of calls are generated under microprocessor control. DTMF originating and dial tone detecting circuits as well as circuits for transmission and loop polarity testing may be added to the line interface and controlled by the same microprocessor. The system has a microprocessor controlled display and keyboard terminal by means of which instructions for and reports of the results of the tests are obtainable.

Abstract: Synchronous operation of any number of digital switching units of a TDM system is maintained by interconnecting the switching units to a timing signal highway which distributes timing signals generated by sources of such signals in any one of the units. The units are connected successively in a chain by timing signal distribution control lines. Validity signals are generated and transmitted by circuits in each unit along the lines so as to provide for transmission of timing signals generated in the first switching unit on to the timing signal highway and switch over of the timing signal generating function to successive ones of the units when the timing signal generation in preceding units becomes faulty.

Abstract: A time division digital communication system which does not require a common control unit for accomplishing interconnections, having a plurality of modular switching units. The switching units are identical and each unit has its own port circuits to which subscriber lines and/or trunks may be connected, service circuits, a time slot interchange and a microprocessor control and timing unit. The switching units are in direct communication via separate send highways, one for the port circuits and the other for the service circuits of each switching unit. The microprocessors of each switching unit are also in direct communication by way of control lines. The inter-switching unit send highways are connected to separate channels or groups of memory locations in the time slot interchanges of each of the switching units.

Abstract: An operator complex in which control signals relating to key lamp and alphanumeric display operation and key transition data are carried between the operator console and the PABX system on a multiplex highway or radio transmission link to permit virtually unlimited spacing between the operator console and the associated switching system. The operator console includes a send control system and a receive control system. The send control system detects valid key transitions and formulates a message concerning such detected key transmissions to be sent to the common control in the PABX. The receive control system receives messages from the common control indicating key lamp or alphanumeric display information and decodes these messages to effect selective control over the display.