Abstract: In a point-to-multipoint system (SYS), particularly a video-on-demand system, comprising a send unit (SERVER) in the form of a server and a plurality of receive units (DEC) in the form of decoders, a new version of the system software for the decoders is to be transferred to the latter. This is done by taking the following steps: 1. An announce signal containing the information that the new system software or part thereof will subsequently be transferred is transmitted from the server to all decoders simultaneously. 2. The system software or part thereof is transferred in the form of data packets from the server to all decoders simultaneously. By the advance information in the form of an announce signal which is transmitted to all decoders by the broadcast method, the decoders are notified of the forthcoming transmission of the current version of the system software, whereupon they can prepare for the reception of the new version.

Abstract: A service-on-demand system (SYS) includes a facility (EIN) which is designed to assign transmission channels to terminals (END1, END2). To accomplish this, the facility (EIN) contains two interfaces (S1, S2) for connecting it to two groups of terminals (END1, END2), a memory (MEMO) which holds an assignment table containing entries on currently available and currently busy transmission channels for transmitting services requested from terminals (END1, END2), with a variable assignment of transmission channels to terminals (END1, END2) being possible regardless of which group the terminals (END1, END2) belong to, and a control unit (CTRL) which coordinates the assignment. Only those transmission channels can be assigned which are considered currently available in the memory (MEMO). The transmission channels are not permanently assigned to groups but are largely freely available to all terminals (END1, END2).

Abstract: In a point-to-multipoint system (SYS), particularly a video-on-demand system, comprising a send unit (SERVER) in the form of a server and a plurality of receive units (DEC) in the form of decoders, a new version of the system software for the decoders is to be transferred to the latter.

Abstract: A buffer or other communications resource in, e.g., an ATM switch element receives random data which is then used by different data sinks. After the data has been outputted to the data sinks, the communications resource (e.g., the memory locations of the buffer) are released, i.e., labeled as free again. However, a resource which is not marked as free as a result of an error (whether erroneously the data is not retrieved or whether the release procedure is erroneous) remains blocked. To avoid permanent blockage of those memory locations whose contents have been in the buffer so long that they definitely (or at least very likely) should have been called for, information on the time of entry is stored together with the data. All memory locations are checked at regular intervals for the age of their contents. Upon attainment of a predetermined age, the location is labeled as free.

Abstract: Prior Art/Technical Problem: During the establishment of a call through a switching network 20, the path is selected on the basis of the instantaneous loading of the switching network and maintained during the call. The problem of eliminating local blocking by rearranging existing connections has not been satisfactorily solved because of errors occurring during the rearranging process.Basic Idea: Provide in an ATM exchange operating with virtual connections the same devices which assure the correct order of the cells in the "connectionless" mode.Solution: Each output of the switching network is followed by an output unit 30 which ensures that the cells are output in the correct order.Advantage(s): Virtual connections can be adapted to the instantaneous loading of the switching network error-free at any time. The assurance of the correct order can be implemented so as to largely compensate for delay jitter.

Abstract: In practice, switching is a continuously changing mixture of point-to-point connections, point-to-multipoint connections with low fanout, and point-to-multipoint connections with high fanout. The switching elements of a switch optimized for point-to-point connections are additionally enabled to copy a few input signals for an arbitrary number of outputs, so that a very large number of copies is attainable for few input signals. This switch is supplemented by a copy switch which serves exclusively to make limited numbers of copies for a large number of input signals, which are then switched in the (group) switch as point-to-point connections. Point-to-point connections are operated as connectionless connections, but outside the switch act as virtual connections. Point-to-multipoint connections are operated as virtual connections (connection-oriented) by means of connection tables.

Abstract: To be able to load an ATM switching network as efficiently as possible, the successive cells of one and the same connection are routed to the output by as many different paths as possible; however, mutual overtaking of successive cells must be avoided or corrected. Each cell is held at the output until it is certain that no older cell can be buffered in the switching network. Before the cell is passed on, a check is made to determine whether the cells received from the switching network later include an older cell which must be passed on before that cell. At the input end, consecutive numbers ("Sequence Numbers") are allocated to the cells. A buffer (1) at the output end is operated, at least in part (1 . . . d), in the manner of a shift register, thereby introducing a predetermined delay. Prior to the output of a cell, at least the shift-register-like portion of the buffer is examined as to whether a cell written in later is to be put out earlier: if so, the two cells are interchanged.