Tav means “Mark, sign, cross.” An X or cross was the ancient Phoenician form of the letter Tav. Ancient Rabbis called Tav “the seal of truth, god, creation”. A signature is the mark one makes that states law or truth. We sign a document with our name to indicate that it is true and binding.
The ATM uses an electronic signature or mark called a PIN (Personal Identification Number). This signature is kept in the person’s head. This fulfills prophecy.
And he causeth all the people, small and great,
rich and poor, free and slave,
to be given a mark
in their right hands or in their foreheads,
And that no man might buy or sell,
save he that had the mark,
or the name of the beast,
or the number of his name.