http://www.cisco.com/en/US/products/hw/gatecont/ps514/produc...Resetting the Cisco ATA to Factory Default Values
It is possible that you may, under some circumstances, want to reset the Cisco ATA to its factory default values. For example, this is the only way to recover a forgotten password without contacting your Cisco representative.
To perform a factory reset, you must use the voice configuration menu and follow these steps:
Procedure
Step 1 Press the function button on the Cisco ATA.
Step 2 Press the digits 322873738 (FACTRESET) then press # on your telephone keypad.
Step 3 Press 3 on your telephone keypad to confirm that you want to reset the Cisco ATA, then hang up the phone.