Abstract: Program-controlled communications systems KA are connected with a service center SZ, and, in case of error, transmit error messages M to the service center SZ. The messages contain program-specific error information fi. Error information fi and allocated programs APSE provided for error removal are stored in the service center SZ. Through a comparison of the error information fi transmitted from the faulty communications system KA with the stored error information fi, the programs APSE provided for error removal can be determined. These programs APSE are thereupon transmitted to the faulty communications system KA, where they at least partly replace the previously used programs APS. The program change can ensue during on-going operation, if the transmitted programs APSE provided for error removal are stored in an additional memory ZSP and an at least partial switching over takes place to this additional memory ZSP. The error removal is considerably simplified by the method.

Abstract: A method enables a system program to automatically fashion itself into a system program version matched to the storage capacity of a system memory when loaded into a system memory of a program-controlled processing equipment. To this end, the system program is subdivided into a basic program module and into at least one supplementary program module. A program loading sequence first causes the storing of the basic program module and calculates the available storage capacity. Depending on available storage capacity, storing of program sequences of the supplementary program module may then be enabled. A branch address list onto program sequences of the supplementary program module is deposited in the basic program module. The addresses of the program sequences which are not loaded may be modified in the branch address list.

Abstract: A central clock unit has a ring generator for generating ringing signals and a DC voltage source for generating display signals. With the assistance of the central clock unit having a switching unit that is controlled by a central processor unit, either the ringing signals or display signals are transmitted to an analog communication terminal via a ring down line and a line connection unit. Within the line connection unit, a switch is controlled by a ringing-display procedure to generate the desired rhythm of the ringing or display signal. A read/write memory unit within an I/O device is divided into dedicated memory sections to eliminate any delays associated with the control of the ringing-display procedure. The dedicated memory sections are used to store information which is written to or read from the memory by the I/O device and the central processor unit.