The dirty secret of digital phones and making 911 calls

By Marty Focazio

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Basic telephone service is, by far, the most advanced technology that people use every day. While it seems that everyone has a cell phone and uses Internet voice over IP, the reality is that both technologies still have quite a way to go before they can do some of the neat tricks that ordinary switched phone service can do.

The best way to see how much more cell phones and Internet voice have to learn from the "old-fashioned" telephone networks is to look at how 911 calls are handled. When you dial 911 from your home phone all sorts of cool things happen.

First, your call is routed to a special phone switch, one that carries emergency service. This switch is connected to a database of the physical location of the phone wires that were used to originate the call, and the dispatcher gets the address of the caller on the screen. Sometimes there's even a map of the location, and in really fancy systems, a map and routing data is transmitted to a computer in the emergency vehicle. In many systems, the 911 operator can "seize" the line - preventing other calls from coming in, and keeping the line connected even if the caller hangs up. The 911 calls go to a Public Safety Access Point - the place where trained 911 operators and dispatchers work to assign and direct emergency service workers.

However, these Public Safety Access Points also have to deal with calls from cell phones and, more recently, Internet voice calls. To say that the public safety agencies are dissatisfied with the VoIP situation is putting it mildly:

"Routing VoIP 9-1-1 calls to 10-digit emergency numbers disrupt and strain the limited resources of PSAPs, which are already struggling to provide wireless E9-1-1 capability." - The Association of Public-Safety Communications Officials (APCO) International President Greg Ballentine. 

In both the cell phone and the VoIP phone, these neat technologies seem to be everything "ordinary" phone service is and more. But they are not quite the same in important ways.

There are two key differences that really matter. The first is that cell phones and Internet voice calls are routed via ordinary telephone lines, through non-emergency phone switches. When you call 911 via a cell phone, your call is often run to an office telephone system that happens to be at the Public Safety Access Point. While there's considerable effort and progress on handling 911 calls from cell phones effectively, they are still the bane of the dispatcher's day. They often have to re-key your phone number and try to guess or figure out your location, leading to exchanges like this:

Cell phone caller: "I saw an accident on the road."
911 Operator: "What road?"
Cell phone caller: "I don't know"
911 Operator: "Where are you now?"
Cell phone caller: "In my car"

Some primitive, slightly effective cell phone location systems are being rolled out, but GPS does not work indoors, and cell phone triangulation is - at best - an iffy proposition in urban areas, and pretty much useless in rural areas.

For Internet voice calls, the situation is more complex. For some Internet voice carriers, e911 calling is still a bit dicey. (See for example the service offered by Packet8 here -  and note this little tidbit:

"You will soon be able to check the exact status of your E911 service relative to your geographic location by dialing 933 from your Packet8 phone.").

And AT&T CallVantage's terms of service goes into a lot of detail about what their customers can expect from 911 service here:

" YOU WILL NOT BE ABLE TO PLACE TRADITIONAL WIRELINE 911 OR E-911 CALLS
FROM TELEPHONES CONNECTED TO THE TA OR FROM COMPUTERS DOWNLOADED WITH
THE AT&T SOFTPHONE PROVIDED FOR THIS SERVICE. YOU ACKNOWLEDGE THAT WE
HAVE TOLD YOU THAT THE SERVICE DOES NOT SUPPORT TRADITIONAL WIRELINE
911. YOU AGREE TO ADVISE ALL INDIVIDUALS OF THIS LIMITATION WHO MAY HAVE
OCCASION TO PLACE CALLS OVER THIS SERVICE FROM THE LOCATION AT WHICH YOU
HAVE INSTALLED IT. YOU ACKNOWLEDGE THAT AT&T DOES NOT OFFER PRIMARY LINE
OR LIFELINE SERVICES, AND THAT AT&T STRONGLY RECOMMENDS THAT YOU ALWAYS
HAVE AN ALTERNATIVE MEANS OF ACCESSING 911 SERVICES VIA A TRADITIONAL
PHONE LINE OR A WIRELESS PHONE."

This brings the very real possibility that an Internet voice customer would not be able to dial 911 at all in the event of an emergency. However, putting 911 service on an Internet voice account is not actually giving customers real 911 service.

Remember the neat little tricks that a 911 operator can do with real 911 service - like get instant address data, hold a line open and so forth? 911 calls placed on most Internet voice providers is routed over ordinary phone lines to an ordinary phone system at the Public Safety Access Point. In some cases, the call is not even routed to a Public Safety Access Point, it goes to what amounts to a call center, where an operator will try to figure out which Public Safety Access Point is supposed to handle your call. For a long series of horror stories and call problems see www.911dispatch.com.

Most recently, AT&T CallVantage has terminated accounts in areas where it can't guarantee E911 service.

A new twist to help solve this problem is a product and service from Ooma.com, that uses your existing landline phone to make 911 calls, but places other calls over the Internet.

Internet voice is, in many ways a great example of fancy features overriding core functionality and stability. While it's great to have 3-way calling, caller ID, call forwarding and all these neat add-ons with the service, this can't obscure the fact that neat features on top of an incomplete base of functionality can be a - literally - fatal flaw. I'm reminded of MS-Word, which is smart enough to intercept my keystrokes and offer "help" when it detects that I'm writing a letter - but it still crashes more than I want when saving a document. Clearly, flash has outstripped function.

The point of all of this is not to say that Internet voice and cell phones are a bad idea - they are not. But they are far from ready for mass deployment, despite the increasing numbers of people planning to use only cell phones and Internet voice for their primary service. If a new technology comes along proposing to improve on an old one, don't forget to look at the really hard parts of implementing the old system and realize that these parts - the deep, complex and critical aspects of the technology are some of the most important features - and ones that can't be left out.