Circuit arrangement for saving data in communication switching systems

摘要

When the power supply of a switching system fails, all data necessary for the operation are to be saved so that they are immediately available again when the operation is restarted. For this purpose, it should not be necessary to hold any additional mechanically driven information carriers in readiness. For this purpose, an electrically programmable flash-type read-only memory is connected to an address bus and to a data bus to which the control is also connected. When the power supply fails, all data are re-stored, during a period in which residual energy is still available, from a data memory into the flash-type read-only memory which maintains its content even when the power supply fails. When the supply voltage returns, all data from the flash-type read-only memory pass back into the data memory of the switching system. Using the flash-type read-only memory and the connection and operating conditions provides an inexpensive space-saving arrangement for saving switching data.