Avoid SIP usage restriction and bandwith problems using CallBack options.
Automatic swith-over to DISA (Call-Trought) when you lost you wifi or 3G access.
Check the status of your corporate extensions and see if your colleges are free. You can even use chansply or whisper on authorized extensions.
Integrate with your firewall using PortKnocking or included client for free dinamic DNS Services (DynDNS or non-ip).
Protected Access to Asterisk AMI interface for advanced admin options. Send AMI or CLI comands remotely to control your PBX, restart it remotely, or monitor peer connections!
Implement Call-Forwarding or Follow-me for your extension. Pickup your corporate extension at your mobile!