Hi friends. I have thought of creating a mobile application where a user with a mobile phone can send an sms to an application and can also receive an sms from the application. I want this application to work in a way like applications work over a gsm network. I am not in position to use the mobile operators but would like to create my application in a simulation environment. I read in some site that i can create my application and use smppsim to simulate the SMSC. The problem is i don't know how to go about this stepwise. I just need some insight on the application components needed right from the mobile phone client to the server side and how to interconnect them. Basically if there is a way someone would tell me where the server application would be placed and how to access it from the mobile client, I'll be very grateful. Am really new to sms but really want to do an application that integrates it. Any help such as links to tutorials with clear illustrations as far as writing java applications that use SMSCs is highly welcome. Thank you