I have two Panasonic KX-NT345 phones I am trying to restore to sell. I go into the setup menu and go to the maintenance tab then go to Setting Initialize. It then says enter password. I have no idea what this password is. I've tried 1234. All ones and zeros. The password can be up to 10 digits, Manual says nothing about it. Tried all basic passwords I can think of but no success. Any suggestions?