I've seen an NIU before, but you said the system looked "GTE" and I got confused. I'm 32 and I had to really dig to think of a time when the PHONE COMPANY installed phone systems - now it makes sense!
Let me ask you this: In a 1A2 system, where would the CO lines I need to use for the future Avaya system be? At the big ole block in Pic A, or somewhere adjacent to the 1A2 in Pic B? I will trace this all out on the day of the install, but any granularity I can get in the meantime the better I can strategize. There's a good possibility the NIU itself is somewhere near the 1A2 in the basement (this is also where the city power comes in) and I just didn't notice it.
I hesitate messing with anything over there as the system is in a very precarious state right now. If something goes wrong I won't be able to fix it. Hence the stupid questions.
