15-07-2014, 10:27 AM
It is almost certainly more than a coil and a capacitor - it probably is more than NFC, most likely RFID - NFC is typically only a few inches or contact - ski passes normally work if they are in your salopette or jacket pocket (sleeve or front) which is RFID territory... in practice, an Active Reader Passive Tag (ARPT) system...
The card is normally "passive" and has no internal battery - they are powered by EM from the gate reader which wakes up the card for long enough for it to typically respond with a GUID (globally unique identity number, typically 128 bits long) at 13.56 MHz - range is about 1.5 to 2 metres...
The gate access system looks up the GUID in its database to see if the card has been reported lost/stolen or is out of date/out of area or in use elsewhere in the resort (i.e. its a clone) and (on some systems) can pull up a photo of the legitimate holder (which obviates the need for a photo to be on the card) and if all is ok, logs the usage and allows the gate to open.
Pretty simple - almost impossible to forge. The cards are stupidly cheap to manufacture as they need not be personalised and contain almost nothing except a way to respond to a query for an id - the cards cost between 10 and 20 cents each in bulk (10,000+ qty). There is no need for a full "smart card" capability for simple access management - the chips are probably something from the NXP MIFARE range or similar...
The card is normally "passive" and has no internal battery - they are powered by EM from the gate reader which wakes up the card for long enough for it to typically respond with a GUID (globally unique identity number, typically 128 bits long) at 13.56 MHz - range is about 1.5 to 2 metres...
The gate access system looks up the GUID in its database to see if the card has been reported lost/stolen or is out of date/out of area or in use elsewhere in the resort (i.e. its a clone) and (on some systems) can pull up a photo of the legitimate holder (which obviates the need for a photo to be on the card) and if all is ok, logs the usage and allows the gate to open.
Pretty simple - almost impossible to forge. The cards are stupidly cheap to manufacture as they need not be personalised and contain almost nothing except a way to respond to a query for an id - the cards cost between 10 and 20 cents each in bulk (10,000+ qty). There is no need for a full "smart card" capability for simple access management - the chips are probably something from the NXP MIFARE range or similar...
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