Abstract: In one aspect, a communication system comprising a message processing computer and a plurality of communication networks, respectively provided with an interface computer that is respectively coupled to the message processing computer in order to reproduce a data flow between the respective interface computer and the message processing computer is provided. In another aspect, a device in which at least one electronic file is requested, the device determines a request message on the communication appliance side, forms at least one communication network request message, and sends the communication network request message to the interface computer(s) in the communication network in question is provided.

Abstract: The invention relates to a method for operating a mobile battery-operated personal emergency signal device, wherein a check of the charge of the battery feeding the personal emergency signal device is performed at least in the course of initiating the personal emergency signal device, wherein the operation of the personal emergency signal device is permitted by a central device depending on the result of the check. The invention further relates to an arrangement for performing the method.

Abstract: The invention relates to a method for operating a mobile battery-operated personal emergency signal device, wherein a check of the charge of the battery feeding the personal emergency signal device is performed at least in the course of initiating the personal emergency signal device, wherein the operation of the personal emergency signal device is permitted by a central device depending on the result of the check. The invention further relates to an arrangement for performing the method.

Abstract: In one aspect, a communication system comprising a message processing computer and a plurality of communication networks, respectively provided with an interface computer that is respectively coupled to the message processing computer in order to reproduce a data flow between the respective interface computer and the message processing computer is provided. In another aspect, a device in which at least one electronic file is requested, the device determines a request message on the communication appliance side, forms at lest one communication network request message, and sends the communication network request message to the interface computer(s) in the communication network in question is provided.

Abstract: An improved switching apparatus, having group couplers (30) and a loop arrangement (6) including a plurality of single loop lines, for communication of digital signals, particularly PCM signals, each comprising several bits at a fixed transmission rate to or from connection circuits (35, 36) connected to a plurality of group buses (31, 32) on each of which digital signals can be transmitted in parallel in a predetermined number of time compartments in cyclic repetition in pulse frames. The group buses (31, 32) are connectable by way of a respective one of the group couplers (30) to the line segments (25, 26) of a respective main bus associated with one of the main couplers (13, 14) connected to segments (7, 87) of the central loop arrangement (6). The two line segments (25, 26) of each main bus serve to transmit digital signals in different directions.