The Zoiper softphone client is a softphone that allows you to register a Gradwell extension on your mobile phone. It is a free application and works with Android (from the Play store) and the iPhone (from the iTunes store).
The setup is simple and you will need to know the extension number and password of the extention you wish to use.
Step one - download the application
First you need to download and install the client on your device. You can find full instructions here.
Step two - configure the client
Scan the QR code below using the scanner on the application (see the instructions above). This will auto-load a Gradwell configuration onto the device and you will then be prompted to enter your extension number and password.