Mitel Corporation

Conrad Lewis

Gino Totti

This invention relates to a switching system testing arrangement which uses a looparound circuit, into which a test signal is injected and received to determine whether the loop is functioning properly. The system provides means for testing individual switches (or equivalent time division counterpart), individual loops and links between switching stages and the network, complete loops between peripherals, short loops between peripherals and their local control units, or any loop that can be set up within the system, without incurring loss of use of parts of the system which would otherwise be required to obtain the loop but are not of interest to test. The control data and test signals are applied, to set up the loop and into the loop respectively, via message transmission paths which are separate from the loop under test. Accordingly any part of the communication circuit system can be isolated for test, reducing substantially the time overhead for determining whether a switching element or stage, or link is operating properly.

Switching system loopback test circuit

This invention relates to a peripheral control unit for a digital switching system. It utilizes a peripheral control network formed of combination time and space division switches which communicate with peripheral cards using a number of time divided lines (channels of which correspond to peripheral units), and communication with the main system central control using a parallel bus connected to a controller and a transceiver, which is connected to the system control via serial time divided lines. In this manner a very few number of wires is required to be connected to the peripheral cards, while allowing selectively simple communication structure and high reliability.

Peripheral control for a digital telephone system

A digital switching system which is comprised of a circuit switching network under control of a main system control for carrying and switching transmission paths for signals transmitted between peripherals (i.e. lines, trunks, service circuits, etc.), and a separate message switching network under control of the main system control for carrying supervisory and control signals related to the status of the peripherals between peripheral unit management circuit controller(s) and the main system control.

Switching system with separate supervisory links

A time division switching matrix which receives time division multiplexed signals on a plurality of input lines according to a first sequence and switches them to a plurality of output lines according to a second sequence, after storage in a data memory. A controller can read any of the signals stored in the data memory and can also substitute data signals on the output lines in place of the signals stored in the data memory. Accordingly the switching matrix controller can receive data signals destined for it on the same PCM lines which normally carry PCM input voice signals, and can transmit data or control signals on the same output PCM lines as would normally carry PCM output voice signals. Controller to controller communication on the PCM lines can thus be obtained throughout an extended network, without providing separate controller communication lines.

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Nepean, Canada

Conrad Lewis