Tony,
The optima default code is 0123
This sounds like the origional optima alarm system which doesn't have NVM (non volatile memory).
It also sounds like the back up battery needs replacing if the alarm system has lost all of its settings!
I can send you the user and engineering manuals from the later version (slightly different)in pdf format if you require them!
Email me johnny_two_bob@yahoo.co.uk
Hope this helps
John
November 2007