US D587301 S1
The ornamental design for a franking system, as shown and described.
FIG. 1 is a perspective view of a franking system showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof; and,
FIG. 5 is a front elevation view thereof.
The broken line showing is included for the purpose of illustrating environment and forms no part of the claimed design.