Softphone and e911

Archived from groups: comp.dcom.voice-over-ip (More info?)

Hello Christopher,

On Thu, 29 Sep 2005 03:03:11 UTC, "Christopher" <christopher00@earthlink.net> wrote:

> I can see the value of VoIP providers proving e911 for TA based services,
> but how do you do e911 if you are using your Softphone via a Wi-Fi
> connection in a public area like a park? Unlike GPS and Cellular
> triangulation, these capabilities do not exist in the wi-fi world....,
> interested in the group's thoughts?
> Regards
> RC

It would be helpful if there was a reasonably universal Location
Protocol that IP Devices could use to locate themselves. I've heard
of some implementations, but none are widespread. Your VoIP Phone
could ask for the nearest location information (in E-911 coordinates)
from the Wi-Fi network. The location might not be very specific,
but hopefully it would at least be close to the public area you were
in.

Such Location Discovery Mechanisms would be helpful in many areas.
Imagine your home PC being able to quickly discover your City and
your browser helpfully locate certain information you are interested
in. Cell phones are likely to have some of this soon, but it may
be more like the cell towers feeding you the data and only that data
that was paid to be broadcast. A similar advertisement system could
help (or bother) motorists that have mapping products in their
vehicles.

As for your Softphone, perhaps it has other location information
that could help you further pinpoint your location. For instance,
a device that could carry on multiple data conversations, such as
a BlackBerry (phone plus PDA plus internet) could recognize that
you just called an emergency number (911) and start a location
discovery process on its own. In this case the BlackBerry is likely
using a cell tower. However, its data terminal could ask you for
further details about your location. Consider a Wi-Fi area that
covers a few square blocks of a city. This extra process of asking
the user to further clarify their location could be selecting
two dimensions between three blocks. That data could be sent to
the E-911 center via a subchannel after the conversation has
started. We don't have that capability today with E-911, but
perhaps the OnStar system has something like it. Cell phones
can also be tracked to some degree. The Wi-Fi network of today
supports connections, just as cell towers used to. Mandates
required the development of location discovery mechanisms
for the cell towers and back into the E-911 system. Perhaps
at some point this will be added to Wi-Fi as well.

David