In the older loads, users could type **##**2 while the phone was off hook to reset the settings to factory defaults. The sequence was changed in the 6.0 loads due to security concerns. In the older loads, users could remotely send that key sequence to a phone and cause it to reset.
This problem is documented in Cisco bug ID: CSCef22943.
To reset the 7970 IP phone to factory defaults, perform these steps:
Note: The phone must be on a network that provides an IP address and TFTP server address using Dynamic Host Configuration Protocol (DHCP), and the phone must be powered through an external power brick. The alternate TFTP setting is erased when using this procedure, requiring that the TFTP server address is provided by a DHCP server to get the phone upgraded.
Power off 7970.
Power on 7970 (with a power brick) while holding the # key.
The lines lamp should blink amber in sequence. Let go of the # key.
The lamps should blink green in sequence.
The phone obtains IP information through DHCP.
The TERM70.default load loads on the phone.
The phone should recover the configuration file from Cisco CallManager. If not, reset by typing **#** to restore the configuration.
If you do not have a power brick connected while doing the factory restore, the process fails because the 7970 cannot TFTP the TERM70.default load from itself with inline power. If you have a console connected, you receive the CDP: power TLV's not detected - assume low power mode - pwr src = 1 message.
If step 3 does not work, upgrade the phone load to the latest version. Refer to the Software Download and look for these files:
cmterm-7970-sccp.6-0-1-Readme.htm (Readme for Cisco IP phone load for 7970 IP phone)