Recently I haven’t had the chance to write many articles, but today I wanted to share with you an article I can cross-post here and also over on The Square Baboon Blog is a blog I share with my college roommate and best friend Joe Sus, where we share photos of various telephones we come across in our day-to-day lives. Note – Joe does a much better job at posting phones than I do. None the less, I digress…

Today’s post is about 911 and calling as well as some of the terminology associated with it. First off, let’s take the place you’re actually calling when you call 911. That’s called a PSAP:

PSAP is short for Public Safety Answering Point. Essentially, it’s the dispatch center you’re routed to when you call 911.

Here’s the cool thing about PSAP’s – they’re regulated by the FCC. What does that mean? Well, if you’re interested in the closed PSAP to you or maybe a PSAP in your general area, you can head over to the FCC’s website and find that information (

Now, let’s take it a step further. When you call 911, the PSAP will use ANI and ALI.

ANI is Automatic Number Identification. In basic terms, this is Caller ID. It displays information about the line calling 911 to the PSAP.


ALI is Automatic Location Identification. The idea behind ALI is that if you’re calling from a land line, the PSAP can get where you live without you even telling them! In terms of a cell caller calling a PSAP, ALI will try it’s best to triangulate your location.

Got all of that? Now let’s throw the wrinkle in to it – the Internet. More and more people are subscribing to Voice Over IP (VoIP) services and when you call 911 from a VoIP line, the PSAP you get as well as your ALI could be completely wrong. Even if you take VoIP out of the picture, ANI and ALI can be “misconstrued” if you work for a company that centralizes all of its telephony and does LCR to try to get the best cost for each call made.

LCR is Least Cost Routing. Essentially it’s sending a telephone call out of the telephone network as close as it can to the number the call is being made to. For example if your company has an office in the Netherlands, but you sit in Chicago and you want to make a call to Amsterdam, LCR would route your call “out” of the Amsterdam office, keeping the call costs as low as possible.

So, we’ve barely scratched the surface, but you can see what all goes in to telephony as well as 911 calls. I hope I’ve given you some food for thought as well as a few new cool terms to use. So, next time you think about buying a VoIP telephone line in order to get LCR, make sure if you call 911, you might be misleading the PSAP with invalid ANI and ALI 😉


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