Or, if you are lazy, like me:
1. Plug your laptop into the DTE port via serial cable.
2. Set up a hyper-terminal session with the following parameters: 38400,8,none,1
3. Pull power adapter out of back of IP Office.
4. While laptop is connected and Hyper-Terminal session is up, plug in power on IP Office and hit escape key on laptop.
5. At the prompt on the screen type the following commands:
1. 'AT-X2' - this erases current config in memory
2. 'AT-X3' - this erases config on flash
6. Cycle power to IP Office and viola, you are back to factory default.
Be aware that when you do this, you wipe out any software upgrades and sets you back to v1.1