a dynamic access random access card is provided with a dynamic random access memory and a source for generating a plurality of reference clock pulses . a control circuit generates refresh operations of the dynamic access memory in response to the plurality of reference clock pulses generated by the source , the initiation of the refresh operations being independent of any external refresh request . the refresh operations are interrupted and the dynamic random access memory is set to a standby condition upon detection of a predetermined external signal , thereby permitting read / write operations of the dynamic random access memory .