If the card supports it.
Simplified:
the card/chip has a list of "cardholder verification methods" ordered by preference
If the terminal/reader supports one of these methods, the card/chip will use it.
Some cards are pin only - notably most of Maestro, Visa Electron and V-PAY cards.
A lot, a majority?, of chipcards issued in the U.S. prefers signatures - I'm uncertain what the percentage is for which doesn't support pin at all.
Some cards are pin only - notably most of Maestro, Visa Electron and V-PAY cards.
A lot, a majority?, of chipcards issued in the U.S. prefers signatures - I'm uncertain what the percentage is for which doesn't support pin at all.