Interesting article about the danish phonecard system, typed and translated from a year round-up issue of Computerworld. CARD CHEATERS ARE STOPPED HERE You probably don't know but you and your phonecard are being watched closely when you're making a call from a cardphone. The phone holds on to your card when you insert it into the slot and while you're speaking, the computer in the phone is checking and registrering the invisible data on the magnetic strip of the card. Everything is registrated: The number of the card, the amount you're talking for, the time of the call, how long it is and the first digits of the called number. The computer makes sure that the card isn't used up and the phone will immediately eject the card and disconnect the call, if the files of valid or black-listed cards show that your card is stolen, a forgery or in some other way unusable. The computer is pretty velinformed. At least once a day it's updated by it's big brother, PMS 200, a central computer. PMS 200 stores the numbers of all cards, even before they are put in circulation. At this moment PMS 200 is keeping track of approx. five million cards, and it follows them through their entire lifetime. All data about calls is kept for 30 days, so the technicians of the phonecompany can track suspicious cards. However, cardphones aren't infallible. Should something go wrong, for instance a phone looses it's speaker or chokes on a card, it will immediately tell it's other big brother PMS 100, which is constantly keeping track of the health of the phones.