1st timer here, my apologies.
Upon inspection the RAM battery finally crapped out and I have a new one on order but what tipped me off was the power went out at the office and the phone system didn't seem to work aside from receiving Line1 calls on only 1 (ID'd 201) 24b Keyset.

I can dial 9 or 701,702, etc.. to get Line1 so I'm guessing it's gone back to defaults.

If I'm going to start to reprogram this ancient PBX where do I start? I've got the manual and figured out the Tech Passcode and Cust Passcode but I'd like to get it back to where all 3 lines work with the old buttons on the keysets. These are analogs coming off of 66 blocks. My problem is that I'm unfamiliar with the terms to know my approach, any help is much appreciated. Thank you for your time.

Joe