ATM Software

Hi all I have got a query for a ATM software from one of our clients. Can any one give me an idea on ATM withdrawal software. My guess is that ATM machines will be installed with Windows CE and there will be server application which can be developed using WCF. From Windows CE application i can call the WCF services and communicate with the server over TCP/IP. Here i have to take care of the data security and all. This is my idea. Am i thinking in the right way. Can any one comment on this.

If I'm right, ATM's run on win2000/win xp, not on CE. Also, I don't think you will find a lot of inner workings on a ATM on a public forum (at least, I hope not... stuff like that is a security risk I would guess).

ya you are right, ATM's run on Windows XP too. can you give me any idea from where i can get more information on this in programing point of view.