Factory Resetting Poly Edge E Series Phones
Power the phone on. Depending on the Edge E model, the Handsfree and Headset buttons should illuminate.
When the lights turn off, press the 1, 5, and 3 keys at the same time. This will cause a menu to pop up asking to enter a password to reset the phone settings.
Next, enter your MAC address as the password (ex: 0004f28619dc) to reset the phone.
Enter the 2nd soft key that corresponds to the mode or encoding to change it to A → abc or a → abc.
Then, for example, to select F, press the 3 key three times.