This project is open source and all software created by Sam & Mike is licensed by and convered by the terms the GPLv3.
You need an android to run the remote COAP gateway software, which connects to the Raspberry PI.
To install software on Android: a) enable applications from unkown sources in your android device b) using your android, navigate to: https://github.com/optimizedsms/SMSGateway/blob/master/app-release.apk c) install and start application.