This paper presents new Signaling System No. 7 (SS7) to IP based Signaling Transport (SIGTRAN) protocol interchanger software and related hardware to implement an improved distributed database based Automated Teller Machine (ATM) network where the countrywide existing IP network can be used. Currently the ATM network is based on fully centralized database environment. This leads to varying transaction time according to the ATM and central database. Moreover, link failure between central database and ATM leads to transaction failure. To overcome this problem, an improved distributed database system for ATM network is proposed. To deploy such network, a new software and related hardware is also presented which discards the need of costly new leased line or dial up connection. Using the software and hardware, the existing IP network can be used for expanding ATM network. Also the cost and benefits of the network is discussed by allocating fragment on different sites.