In the Forum building you can only pay with a Dutch bankcard with pincode or a chipknip. A chipknip is a payment card which can be charged with virtual cash at chipknip charge points. The chipknip is used for smaller expenses such as printing, copying, and buying food and drinks. Every Dutch bankcard has a chipknip which you can use free of charge.
Paying with the chipper is easy, you do not need a PIN code.
You can find a charge point for your chipknip in Forum on the ground floor and on the 1st floor at the coffee corner. If you do not own a bank card with chipknip yet, you can buy one at the reception desk at Forum.