Abstract: Device for inserting several bits in a rhythmed digital train, comprising a osed looped shift register, the shift being controlled according to the rhythm of the train. The register receives, in parallel, the bits to be inserted, the write-in locations depending on the instant at which it is required to have these bits available in order to insert them in the train. Preferably, the train being subdivided into sub-groups (IT) of adjacent bits, the register comprises as many bistable elements as there are bits in a sub-group.

Abstract: PCM telephone transmission apparatus and particularly the use of several ra binary positions in a multiplex frame. These positions are used in one or several units auxiliary to the main unit which processes PCM telephone signals. The auxiliary unit(s) include(s) a signalling time base identical to the signalling time base of the main unit. The counting signals for this auxiliary time base are at a lower rate than the counting signals of the main unit, but they are applied in such a way that a part of the auxiliary time base counts at the same rate as the corresponding part of the time base in the main unit. This structure enables an evolutive use of the extra bits without modification of the main unit.

Abstract: A main pulse train at a main frequency and at least two derived pulse tra at submultiples of the main frequency are transmitted over a transmission path, from a transmitter to a receiver, in the form of pulses of alternating polarity. A first one of the derived pulse trains is transmitted as a single violation of bipolarity in the main pulse train while a second one of the derived pulse trains is transmitted as two successive violations of bipolarity in the main pulse train. The system is applicable to multiple synchronization (bit, frame etc . . . ) in a PCM digital transmission or switching system.

Abstract: The invention comes within the branch of the checking of repeaters formed by two semi-repeaters placed in units spaced out along a transmission network having multiple quads and comprising nodal derivation points for derivating a cable section into several cable sections. It concerns the checking of a predetermined repeater by looping the output of one of its semi-repeaters to the input of the other semi-repeater, by means of a relay logic circuit. The installation comprises means to choose the order number of a derivation, at each nodal point on the network.