911 will accept test calls. You can call the office ahead of time and arrange a test call.

Alternatively you can dial 911, inform the operator it is not an emergency but a test call, and have them verify the phone number and location.

That very much depends on the locale for the latter. If I call 911 and either hang up after they answer or if you say that it is not an emergency but rather a mistake or test, they'll still arrive where I am.

Can they get your location if you call 911 and hang up from a cellphone?

Where I live (in Canada), one time I did some test using a VOIP application, I have no idea why or how, but it caused a call to 911 (I didn't even saw the call...). They called some minutes later to see if everything was alright and when I said it was probably my test using VOIP that caused that, they understood instantly, like it wasn't unusual.

I started Dash911 and more recently MultiAlert911. In every case we've test called a PSAP, as long as we clearly started the call with "this is a non emergency VOIP test call" we had no problems.

Some places require you to get a test authorization in advance, others don't. Everyone allows testing though. Most encourage it.

You're getting downvoted, but I can corroborate. I've called 911 to verify that my VOIP install is providing correct ANI.

If you terminate a PRI into your PBX, you can send whatever number identification you desire.

This is fun for mucking about with coworkers (why is my wife calling me from home in the middle of the day?!?) but serious business for 911 services. You get it right, and you test it by calling them. Identify clearly and immediately that this is not an emergency, but an ANI test and would they please verify that the originating number is xxxxx.

It's fully expected and might even be "required".

While you may send what ever calling ID you wish for regular calls, the local LEC treats 911 calls very differently and typically puts them through 911 screening tables that only allow the CLID owned by the account to pass. If another number is there, it can be stripped out and replaced with the billing number. Entirely up to the carrier.

Regular Calling Line ID to your cell phone may be totally different that Calling Line ID (ANI) to the PSAP 911 center.

Right, CLID and ANI are definitely not the same.

I'm sure there's some variation based on the switch manufacturer or software version at the CO, but it is definitely possible to confuse E911 services by misconfiguring your PBX. IIRC, without configuration (if your PBX sends no data) the network tags the call with 000-000-0000, which might trigger some kind of subscriber table lookup.

But it's also possible to send different ANI based on your originating extension. I had different ANI configured for my and a few others' home VOIP phones (connected by T1s to the PBX in the office, itself connected to the PSTN by a PRI into the router), so that a 911 call from our houses wouldn't summon an emergency response to the office in the Financial District.