Data communications have now become a fundamental part of computing. Networks are based on varied hardware architecture and employ different software implementations. With the advances in information technology, networking becomes an essential component of everyday life in modern society. In the course of day, most of us encounter several activities that involve some interaction with a network. There are many persons behind this great invention of ATM In 1930's, Luther George Simian initially came up with the idea of creating a hole-in-the-wall machine that would allow customers to make financial transactions, John Shepherd-Barron had an idea in the 1960's for a 24/7 cash dispenser, James Good fellow was given the project of developing an automatic cash dispenser in 1965, Don Wetzel In 1968 and John D. White in May 9 1973.The methodology of solving business problem has significant scope advancement. New advancement in computer hardware technology has increased the speed of operation and data transfer and with decreasing cost of data storage hardware it is possible to store large quantity of data, cheaply. This also greatly affects the transferring of data. Such systems have advantage of high throughput, fast response.Keywords:- ATM; Data; security; DBM