in Asterisk, Mr. Fixit

VoIP and 911

A lot of people thinking of switching their phone service over to voice-over-IP (VoIP) are nervous about losing their ability to dial 911. While that used to be an issue it is not anymore, now that Enhanced 911 service is offered by most VoIP companies.

Our new home doesn’t have any landline service, so we’ve been relying on our mobile phones for dialing 911, simply because I hadn’t gotten around to configuring 911 service for our Asterisk-based home phone system. Well, I did that Monday night. It took a few clicks on the Vitelity webpage, some Asterisk-Fu to get the dialplan set up, and then we were in business. It costs an extra $1.49 per month but that all goes to support the 911 system. Which is a good cause, I think.

There are a few differences about dialing 911 from VoIP. First off, its up to you to make sure your address is specified properly when signing up for the service with your VoIP provider. Make a typo and that ambulance will never arrive! I looked mine over three times before I entered the information, just to be sure.

Secondly, like all 911 calls, CallerID is used to associate a caller with an address. Since you can “transmit” any CallerID with VoIP, the 911 call centers get a bit peeved when the number doesn’t match the address. To keep this from happening your VoIP provider will charge you $85 for every 911 call made without a previously-submitted CallerID. Ouch!

Thirdly, your 911 call doesn’t go through immediately. Instead, you get a five-second announcement which says “If this is not an emergency, hang up now,” after which the call goes through. I like this feature as it reduces the chance for false calls, especially since my kids will immediately understand the power of dialing 911. I wish AT&T offered this on their lines, too, actually.

Finally, you need to test your setup, preferably before an emergency! How do you do this, you ask? Well, you call 911. After the dispatcher asks you the nature of your emergency, just say “this is a test call. Can you read me the address on your screen.” Once you hear the address, thank the dispatcher and hang up. If this address is not the one for your house (or business), go back to your VoIP provider’s configuration page and correct any errors there.

Other than that, a 911 call is just like any other VoIP calls. This means you have the typical caveats, of course: if your Internet connection is down, you’ll need to switch to a mobile phone or other means of calling. Most everyone has a mobile phone nowadays so that usually isn’t an issue. And in spite of the bum rap I give cable sometimes, it has been pretty reliable.

That’s all there is to it. Hopefully you won’t have to use it, but now you’ll know how to keep it at the ready.