FIG. 1 is a perspective view taken from from the top, front and one side of my design for a portable card reader;

FIG. 2 is a plan view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a side elevation view thereof from the side opposite that in FIG. 1;

FIG. 5 is a side elevation view thereof from the same side as in FIG. 1;

FIG. 6 is a front elevation view thereof; and,

FIG. 7 is a rear elevation thereof.

The portions of the portable card reader shown in dotted lines do not constitute a part of the claimed design.