wireless home phone 911 compared to landline 911

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Can anyone confirm the location technology of wireless home phone (WHP) 911 calls? Does WHP use GPS technology? Does the GPS technology work indoors?

The e911 phase 2 standard suggested that if the location is determined by cell tower triangulation the location maybe with 100m 67% of the time and 300m 90% of the time. With gps technology it is with 50m and 150 m respectively. While neither of these matches the address based landline 911 accuracy Id like to understand the emergency response impacts of switching to WHP. This could be a consideration in the decision to switch.
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Posted 2 years ago

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David, Mobile Master

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To my knowledge the WHP unit does not include a GPS chip.
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AT&T (parent product) FAQ states that when you call 911, you may have to give them your location.

I have an internet version (VoIP) of a similar box with Callcentric and they require you to register an address where the box will be used. Handy because I can cart my same-number phone down south during the winter and just register the new 911 target address where I will be staying temporarily.

It's a no-brainer solution that works.
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Even if you register an address for 911 purposes with a VOIP provider, you may still need to confirm your address when calling emergency services. Cellular is a bit more reliable than VOIP for detecting location because locating via cellphone towers vs. an IP address is much easier. If you can't provide your address, just leave the call connected and scream.
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Tom B

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Nothing beats a landline for E911 performance. That gives a fairly exact address (assuming that the ANI/ALI (automatic name identification/automatic line identification) database your phone provider maintains is not populated with rubbish). That info is provided to tri-service emergency response agencies that qualify to be 911 primary service answering points (PSAPs).

When a dispatcher at  your local PD or EMS service picks up their phone, their computer usually shows the Enhanced 911 data from the ANI/ALI database of the telco. That includes phone number, the address (often including unit, apartment, etc), the account holder's name, and sometimes other data.

A bit depends on the software in use by the emergency service and the exact data the provider's database spits out. (It's surprisingly varied - I worked on E911 support for RCMP dispatch systems in the mid 1990s and each telco tended to have variations and some had databases with no data entry restrictions so people creating the records somethings made a bit of a mess as far as automated interpretation went).

The ONLY reason I have my step-father and my parents keep their Bell landlines is exactly this. EMS and Police are *obligated* to respond to any 911 call, even one that ends in a hangup or nobody responding at the other end (someone could be in dire distress). The data from the ANI/ALI DB is usually good enough to get a response unit there. VoIP or WHP implementations can get them close, but that could still mean delays in cottage country or high pop urban areas.

You can't always communicate when you need to call 911.