On this topic, Cisco TAC had me once call 911 as a test to confirm the E911 reg. TAC asked for my location and he looked up a special script that I had to repeat to the 911 operator to ensure them it was just a test. I was also told to ask them to verify the address they saw.

Since he had to look up what to say I assume it can be different depending on location.

... which reminds me of a personal story. I once got woken up at home after midnight by the police. They said they had a 911 hangup at this location. I was like "HUH?" and the officer asked me to check my line for noise. I did and it was an insane amount of static on it. I found it very hard to believe my phone somehow went off-hook and randomly dialed 911, but a month later I got my bill and had 20 calls to 411 on it billed that same day.