The GT5000 air voucher charger links to the central platform via the GPRS/CDMA 1x network to conduct real-time data exchange. Then it can conduct relevant service operation to realize the download and printing of the prepayment information. With this data communication channel, we can establish a complete obstacle-free electronic sales system. As all charging card information has been transmitted via the data channel, electronic card sale can much simplify the intermediate links and reduce the overall cost for service operation while the safety has been greatly improved.