using recording by electric charge or by variation of electric resistance or capacitance

Recording on, or reproducing from, the same record carrier wherein for these two operations the methods or means are covered by different main groups of groups or by different subgroups of group; Record carriers therefor > using recording by electric charge or by variation of electric resistance or capacitance

Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor > using recording by electric charge or by variation of electric resistance or capacitance