Radio Shack 3808 Digital Answering Machine "ring telephone ringing phone end" Questions

...Telephone/Answering System that has always worked perfectly until a bad lightning storm hit a couple of days ago which caused the power to go off. The phone is still working perfectly, however the ...

...phone messages there is a three digit code on the back I'm sure this has something to do with it but I need instructions on how to use it. Please help if You can Mahalo Manual - ...