Prentke Romich Company
http://www.prentrom.com/support/article/288

How do I Reset My DeltaTalker?

Summary:
If your device locks up and/or is unresponsive when you press the touch screen you may need to reset the device.

IMPORTANT!  You may lose recent programming when doing a reset.  You will lose all your vocabulary if you have to perform a 4-button rest.

How to Reset the Device:
A reset button is located under the right door on the back of the unit. Press and release this button. Your device should reset and begin to work. 

A 4-Button Reset

If the unit does not reset, perform a  4-button reset.  This will erase your vocabulary and you will have to re-program the DeltaTalker.

First, plug in the battery charger!  Then press and hold the reset button on the back. While holding down the reset button, press and hold any 3 of the 4 corner keys on the keyboard.  Release the reset button first, and then release the 3 corner keys. You should see the ERASE light come on. When the light goes off, you should be able to reprogram the unit.