Verizon Wireless and LG VX5200 phone - two questions

Factual Questions
1

I have two questions about my new cellphone, a VX5200 made by LG.

What is 1X and why is it important enough to have an icon in the display all the time? The “Icon Glossary” helpfully explains that this means 1X. It doesn’t appear in the help software or in the manual index.

What does the icon that looks like a clothesline or a windmill mean? The “Icon Glossary” says it can also have a set of concentric circular arcs to the right. The glossary says if the arcs are there it means “Location on”, and if they aren’t it means “E911 Only”.

Thanks! -Napier

2

“1x” means you have 1x-RTT service available. From here:

The other icons sound like they are for 911 emergency calls. Modern phones can let the emergency operator know your location because they have a GPS receiver. (It’s actualy more complicated, but that’s the executive summary.)

3

If your phone is anything like my Verizon LG (forget the brand number) phone, the default “Location” setting is “On”, which means that your phone is broadcasting its location so that Verizon (or people who pay lots of money to Verizon to get that data) knows where you are (I’m not sure if its on constantly or just when you are making a call). Theoretically this means you should be able to use that capability to call up a map and see your location and also get directions to the nearest [whatever]. If Verizon does have anything like this, I’m not aware of it. I set my phone to E911 only, so that the phone broadcasts its location only when you call 911, as Ex_Chemist said.

4

Does this (the location stuff) mean there’s a GPS unit in there? I’m surprised there’s no other mention of it, and no other use of it.

Or is there some other method, like distance from cell tower by time domain reflectometry and direction by which tower antenna picks up the call?

5

This gets complicated quickly. Different mobile phone operators use different systems to define your location. Most make use of GPS and some make use of timing differences to different base stations. However, all the ones I know about use the network to do some of the necessary calculations and decoding. So, your phone probably doesn’t have a full GPS receiver and doesn’t “know” its location. But your network operator does know your location.

If you’re interested, the details for each wireless operator can be found by creative Google searching.

6

It doesn’t have a full GPS unit in there, so it can’t give you directions or street names or restaurant suggestions, but it certainly can nail down your location to a few feet if you call 911. Verizon doesn’t actively track your location until you call 911.

7
      • I was told that most cellphones (in the US anyway) always find your location by triangulating between three receiving cell towers–not directly by receiving any GPS. When you request it to, the cell-phone provider’s system just feeds your phone a pair of GPS coordinates, and if you’re not in range of three towers, it won’t work.
  • The “default” Location setting makes your phone “ping” the location system at regular intervals all the time as long as the phone is left on–such as every minute or so–and some-number of those pings are saved in a file in last-in/first-out format. The oldest pings get dropped from the file as newer ones are added in. The potential advantage of this is that should you instantly disappear for some reason, the cell phone system will have a record of the last 10 or 20 or however-many “pings” it got from your phone–indicating your last known location. …If you set it to “locate on 911 only”, then it only pings for a location when you dial 911.
    ~
8

I’ve located a reasonable article on this technology in EDN (pdf warning). According to an article in American Scientist (Nov.-Dec. 2005, page 504), Verizon and Nextel/Sprint are using assisted GPS. These two operators serve more than 40% of the US mobile phone users. It looks like Cingular/AT&T use Enhanced Observed Time Difference (E-OTD). I can’t find cites for Cingular’s US market share, but I believe it’s a bit under 50%.

9

Coupla questions:

  1. Why wouldn’t I want to have Location On all the time anyway? If something happens to me and I can’t even dial 911, at least there’d be some clue where to find me once my family starts to wonder. Maybe if I was up to something nefarious and didn’t *want * to be found?

  2. If the phone can usually tell where it is to within a few feet, by whatever means, why not just convert that to longitude and latitude and allow it to be displayed? The information’s there anyway, and maybe it would help me be found if I could read back some numbers.