Abstract: An ATM switching arrangement in which two types of cells are distinguished. A first type of cells is marked as low loss cells and a second type of cells is marked as low delay cells. In the switching arrangement a cell buffer (9) is subdivided into a first memory area (LL) for the low loss cells and a second area (LD) for the low delay cells. In the case of the cell buffer (9) being completely filled, low loss cells get read-in priority over low delay cells. In reading out from the cell buffer low delay cells take priority over low loss cells, unless the low delay area is empty. It is also possible to set a threshold value for the content of the low loss area; when the content of the low loss area exceeds the threshold value outputting of the low loss cells can then be started.

Abstract: The central processor of a telecommunication system is designed for performing many as well as a great variety of tasks. Owing to the more or less accidental character of the demand for processor time (long) waiting times can arise or even overload can occur. The method according to the invention has for its object to avoid this or to control this. As a measure for processor load it is suggested to take the number of calls in build-up phase and the queue length (the number of tasks waiting to be processed by the processor). Based on the value of the maximum number of tasks-in-process determined again and again it is detected whether a new task is acceptable in view of the tasks still waiting to be performed.

Abstract: In telecommunication systems in which tasks are performed collectively and centralized by the processor of the central controller, the problem is encountered that this central control may be overloaded. The method in accordance with the invention has for its object to prevent this by rapidly detecting an imminent overload. The number of tasks (for example calls) being processed and the number of idle jobs which were performed are taken as a measure of the load. On the basis of the continuously actualized value of the maximum number of tasks which can be handled it is determined at each new task (for example a call from a subscriber) whether the maximum calls in the process of being set-up determined for that period is not exceeded.

Abstract: Method for the transmission of data packets from a plurality of substations to a main station via a channel which they have in common, the main station transmitting a synchronizing signal which on reception in the substations indicates the beginning of a period which has been subdivided into a sequence of time slots of mutually equal lengths, those substations which have a data packet ready for transmission to the main station transmitting this packet to the main station in a time slot which was randomly selected from the said sequence of time slots, and the main station classifying the time slots as successful or mutilated depending on whether an unmutilated or a mutilated packet is received, in the main station the number of time slots of a next following period or frame being adapted on the basis of the detection of the number of successful and mutilated time slots and taking the conditional probabilities of the occurence of successful and mutilated time slots, given the number of substations transmitting