Abstract: A multilevel data base memory structure for use by the processor control of each of a plurality of interconnected telecommunication switching systems so that communications between any two of the systems can be established with minimal interaction by the users. A comprehensive directory number plan provides for the allocation of blocks of at least one hundred directory numbers (i.e. 2400-2499) to the stations or features of each switching system. For those directory numbers serviced by a switching system the thousands/hundreds digits are utilized as addresses of locations of the memory structure first table level, the contents of which are pointers to various sections of a second table level. Within each such section the tens/units digits are used as addresses to define a location having stored therein an ultimate system function representative of, for instance; a standard call, conference call, speed dial . . . etc.

Abstract: A telecommunication switching system utilizing immediate-start type trunks assures the collection of dial pulse information in receiving registers, via a network connection, by employing a dial pulse delay within each such trunk circuit for holding dial pulses a predetermined period of time before transferring the pulse information to the registers via the established network connection.

Abstract: A telecommunication switching system adapted to be connected to lines and trunks has a digital switching network and a control complex for executing system operational functions by program operated processors in response to dialed numbers received from stations in separate customer groups. Customer groups are groups of stations on discrete sets of lines served by the system, all customer groups sharing the hardware forming said switching system while all operational functions are normally separately executed for each customer group in response to dialed numbers included within a separate comprehensive number plan for each customer group. Representative system operational functions include processing standard calls between stations on lines in the same customer group and processing conference calls between multiple stations.

Abstract: A microprocessor control complex for a telecommunications switching system disclosed in the context of a digital time division multiplex switching system. The control complex is arranged as a cluster of hardware identical microprocessors in a distributed processing configuration wherein each microprocessor is provided with its own memory and clock and is programmed to perform a portion of the total function of the switching system. Each microprocessor performs the functions assigned to it independently and asynchronously of the others. Data is transferred between microprocessors in a manner which minimizes the amount of time spent in interprocessor communication. This communication is accomplished via interprocessor buffers which provide dedicated communication channels between partner processors while allowing those processors to continue to operate asynchronously. The distributed control complex allows the software to be modularized with resulting economies in program generation and debugging.

Abstract: A method and means for providing a remote data station with access to the program memory of a stored program common control telecommunications switching system. The control complex has an input/output port and a modem for interfacing that port with its switching network. The control has the capability of setting up connections in the network between the modem and a selected trunk. Incoming connections to the modem are given only limited access to the stored program control, that access for the purpose of analyzing incoming data to detect a predetermined code. In the event the predetermined code is detected, the incoming connection is taken down, and an outgoing connection established to a distant station by dialing the number of an authorized station which is stored in the program memory. Full access to the program memory is then allowed, such that full access is provided only to stations whose telephone numbers are stored in the memory of the switching exchange.