November 28, 2008 8:51 AM GMT
Calling card is wild used in a VOIP system . A VOIP calling card system itself also play a VOIP trunk service. But for GSM or PSTN , this solution will make the call cost high , because the call cost will be 2 way cost. User to Server & Server to callee . So we use GPRS data communication to check the calling card PINS , and send the remain credit to the payphone. And then payphone will allow user dial out . After user finish the call , payphone will update the remain credit , and send back the Call detail record .
I think this solution is perfect , General a secuity smart card cost is very high , a magnetic card cost is just 1/3 or less .
This system also can very be easily to be add extend value service.
For example , is a payphone operator himself also want to becoma a GSM service provider Air time distrubtor , to add a small flow on the server ,so user can use calling card to buy air time..
Do anybody can advise me what should I notice ?
This system is a pior system of public payment system , if you have any comment , and suggestion , or you want to sharing your experience , you are welcome to contact with me .
My email : firstname.lastname@example.org