Le Material Telephonique

Le Materiel Telephonique Thomson-csf

Jean-Paul Lager

Marc P Dieudonne

Jean-Baptiste B Bouvier d'Ivoire

Hieu K Nguyen

Daniel A Vautherin

Michel J Cauhape

A circuit for monitoring the operation of a time-division switching network, in particular, a circuit for checking the continuity of the switching network speech paths during actual communications. The circuit includes a plurality of monitoring Groups (I, II . . . N) which operate simultaneously under the control of a microprocessor. Each monitoring group is connected to all the incoming trunks via a synchronization and multiplexing circuit and to selected ones of the outgoing trunks, via a multiplexing circuit. The invention is applicable to telephone exchanges.

Monitoring circuit for time-division switching network

Methods and apparatus for converting time-division data signals received over an incoming trunk having v.sub.e channels into time-division data signals for transmission over an outgoing trunk having v.sub.s channels (where v.sub.s &gt;v.sub.e). The device includes means for storing the data bits contained in each incoming frame; means for reading at an intermediate frequency f.sub.i, during read enable periods, the stored data bits corresponding to v.sub.e busy outgoing channels and for evenly distributing v.sub.s -v.sub.e free outgoing channels amongst the v.sub.e busy outgoing channels, during read inhibit periods; and means for transmitting at a frequency f.sub.s the data bits read at the intermediate frequency f.sub.i. This device may advantageously be used in PCM telephone exchanges.

Method and apparatus for converting time-division data signals received

A receiver for simultaneously transmitted clock signals of frequency F (HC) and auxiliary signals of frequency f (HS), F=kf, k=2, 3, 4, . . . , said clock and auxiliary signals being transmitted as a modified clock signal (HM) wherein one clock pulse is omitted every k clock pulses. The modified clock signal is simultaneously transmitted over three, nominally identical, transmission circuits (e.g. as HM1, HM2, & HM3). The receiver comprises the combination of a selection circuit (1) for generating a normal modified clock signal (H), even if one of the three received modified clock signals should be absent, and a signal separation circuit (2) for reconstituting both the clock signals (HC) and the auxiliary signals (HS). The receiver further includes an alarm circuit promptly detects transmission failures or impairments, even though the main portion of the circuit continues to operate properly.

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Bougival, France

Jean-Paul Lager