Ron Onrust sent me this link to an article in the RFID Journal on the ViVOtech contactless payment solution.
ViVOtech's reader connects directly or wirelessly to a retailer's existing POS system to enable contactless payments without requiring the retailer to invest in a new infrastructure to add xontactless payments. The reader receives a unique card number and a security code from the contactless gift card and transmits that data to the retailer's POS system in a format identical to what is generated when credit cards and gift cards with magnetic stripes are swiped at a POS device.
The new ViVOgiftcard adheres to ISO standard 14443B and can operate over multiple frequencies, including 134 KHz, the same frequency used by ExxonMobil Speedpass system. The only information stored on the ViVOgiftcard is the customer's card number and a security code that changes at each reading. The monetary value on the card is stored centrally on a retailer's back-end server.