Cisco – How to reset a Cisco ATA 186 to factory defaults

I have an old Cisco ATA 186, configured by an extincted Phone Service Company, it is password protected and on TFTP client mode.

I tried to reset it with IVR FACTRESET code (322873738#) but it ask for password before I can press * to confirm.

I called to Cisco Support but they cant help me because I haven´t a contract.

Is there another way to reset it?

Here is what I have found so far:

Q. How can I recover the ATA 186 if I forget the password?

A. There are two important passwords for ATA 186. One is the
UIPassword, which protects access to the ATA web server interface. The
other password is the EncryptKey, which protects access to the TFTP
profile. If you forgot the value for the UIPassword but still have
access to provision with TFTP, you can modify the UIPassword through
TFTP. However, if you are not provisioning via TFTP, or you forgot
both passwords, open a case with the Cisco TAC to further
troubleshoot. Refer to Contact TAC to open a case.

Cisco ATA 186 FAQ and Common Issues