Speaking of fire alarms - we just had an alarm up on the 10th floor of the building I work in (I'm on the 8th) - folks did the right thing (evacuate down 2 floors - aka my floor), but the bad one - when they grabbed the fire phone - NO ONE ANSWERED!! 10 minutes - no one answered - many just walked out. The only reason I knew was my office is right by the lobby/staircase where the phone is
I saw what was going on, had my bag grabbed, let the folks on my floor know what was going on, and was standing by the warden phone (as I'm the 8th floor warden).
We got the all clear
What was interesting was that they got the 'alert tone' (aka the 'Macys tone') which is no longer supposed to be used. For the last N years (I think it was changed post 9/11) is that you ever get the 'full alarm' or NOTHING
Check with your local fire marshal about the alert tone on a voice evacuation system. Different jurisdictions have different rules about some things. Your local AHJ (Authority Having Jurisdiction - usually the fire marshal) can set requirements above and beyond what national fire codes require.
As to the fire phone, I'd definitely have someone check it out, ASAP.