Read out driver card at home???

Hello first of all, with my main employer I drive only with an analog speedometer disc and about 4 – 5 times a year I drive as a backup driver at another company digitally. I can of course have my driver card read out at my second employer, but since the distance is too large, I can not drive there every time or every 21 to 28 days. Now to my questions: Is it legal if I regularly read my card myself with my own card reader? And do I have to use the o nline or can I burn the data to CD or to 2 CDs (a backup copy)? If I read the data myself and store it at home on CD, how does it work if I get into a police control and these want my data? Would it be better to have the data on a USB stick with me? How long do I have to store/save my data? I have read somewhere that you have to keep the data for at least a year. Can someone give me a good and uncompli recommended card reader? Many thanks in advance, Tigg