Abstract: Protocol adapter equipment for a telephone set including a processing unit (14) provided with hardware and software means organized to enable the telephone set to operate in compliance with a circuit mode communications protocol via a communications link (3) of a telephone network (4), and a telephone set provided with such equipment. The equipment includes a coupler (18) enabling it to operate in packet mode via the communications link in addition to the coupler (17) enabling it to operate in circuit mode, the two couplers being connected to said communications link via a selective switching member (16) and being governed by the processing unit of the set, which unit is provided, for this purpose, with means including a packet mode protocol manager (20) in addition to a circuit mode protocol manager (19).

Abstract: An interface between a memory that has "n" address bit inputs and a processor which has "p" address bit outputs (where p<n) and "q" programmable data bit outputs (where q.gtoreq.n-p). The interface includes a logic circuit connected to a byte select bit output, to a memory read-write command bit output and to an appropriately programmed one of the "q" programmable bit outputs of the processor. The logic circuit produces a least significant bit address bit input AI0 defined by the equation AI0=R/W & byte-s OR R/W & I/O0. The interface connects the remaining "p" address bit inputs of the memory succeeding to the "p" address bit outputs of the processor, in order, and connects the remaining "n-p-1" most significant address bit inputs of the memory to the same number of appropriately programmed programmable bit outputs of the processor.

Abstract: A method and apparatus for playing back a sequence of images from a run of component images successively supplied in digital form by a remote source to a receiver apparatus having the function of playing back the images of the sequence at a given rate, and in which each image constitutes an independent set that is received in the form of data trains. The apparatus includes verification that each received data train and each run of trains making up a set is valid, storing the most recently received valid set, reconstituting image signals from the most recently received valid set, and a clock for locally and independently generating clock signals for triggering visual reproduction of images as a function of circumstances.

Abstract: The header of each packet contains a virtual channel identifier. The virtual path identifier is a packet distribution agent enabling a packet to be distributed when the packet is travelling over a public network, and the virtual path identifier is a packet-routing agent enabling the packet to be routed when said packet is travelling over a private network. Each time a packet is transferred from a private network to a public network, routing data contained in the virtual path identifier is shifted to a reserved portion of a virtual channel identifier that is also contained by the packet, and it is replaced by distribution control data. Each time a packet is transferred in the opposite direction, the distribution control data in the packet is replaced by private network internal routing data.

Abstract: In a method of synchronizing nodes of a private telecommunication network to the best available clock at all times, each node of the network is normally synchronized by externally originated clock signals which reach it via a point-to-point digital transmission link input. Two node inputs are preselected as main and backup master clock inputs and each node is selectively preselected as a potential supplier of clock signals to each of the nodes to which it is connected by one of its master clock inputs, the nodes of the private network interconnected in this way determining a synchronization tree. In the event of loss of clock signals an exchange of information is instigated between adjacent nodes to reconfigure the synchronization tree that these nodes constitute so that each of them is synchronized to the best available clock.

Abstract: The terminal housing firstly includes a base (1) which contains circuits corresponding respectively to a telephone circuit (4) and to a power supply (5), a roll (8) of continuous print medium (9), one or more motors (6) actuating both a medium-cutting device and drive rollers (10, 11) for a document to be faxed and for the continuous print medium, and secondly includes a hinged cover (2) which contains at least a man-machine communication arrangement (16, 17), a monitoring logic circuit (13), a scanning head (14), and a print head (15), and which is hinged at one end on the base so that it is alternately either closed on the base so as to close the housing and to position the heads relative to their associated rollers, or open so as to give access to the essential components both inside the base and inside the cover.

Abstract: A method of forming a franking impression on a mail item and apparatus for forming the franking impression is disclosed. Material which is switchable from one stable state to another stable state by exposure to light of predetermined wavelength is deposited on the mail item while in one state and a selected region of the deposited material is exposed to light of the predetermined wavelength to effect switching of the selected region to the other state and thereby to represent franking or other secure information.

Abstract: Thermal printing apparatus is disclosed in which a thermal transfer ink ribbon (14) is drawn from a supply spool (15) past a thermal print head (12) in ink transfer engagement with an item (17) on which printing is to be effected. The used ribbon is wound upon a take up spool (16) which is driven to apply tension to the used ribbon to peel it from the face of the printed item. Drive (43) to the take up spool is controlled by a pivoted member (22) which actuates a switch (26) to apply drive when the ribbon is slack and to terminate energisation of the drive as the ribbon becomes taut.