Ask MetaFilter questions tagged with CDMA

CDMA security?

y6y6y6 — Tue, 28 Jul 2009 09:03:01 -0800

How worried do I need to be about bringing my cellphone to the DEFCON ~~hackers~~ security convention? I'll have WiFi and bluetooth turned off. Treo 800w. Sprint. Not roaming.

It would be very nice to be able to bring my phone with me for web and email, etc. I know that if I do that over Sprint's data network this would normally be secure. But if someone is going to try cracking CDMA, spoofing access points, etc, DEFCON is one of the places you would find that.

Googling is not helping me get a more comfortable technical answer to this issue. I'm hoping someone who is more knowledgeable about cell phone security can give me a realistic idea of how dangerous it might be to check email in this environment (assuming no WiFi usage).

What is the technical bible of the cell phone industry?

Pastabagel — Tue, 19 Aug 2008 09:05:25 -0800

Asking for a friend: What is a very good technical text for understanding current and future wireless telephony standards, beginning with the basics about CDMA and TDMA and covering through 3G, LTE, LTE-Advanced, WiMax and beyond? He's looking for the "Bible" of wireless telephony, the equivalent of what Horowitz & Hill is to basic electrical engineering. Thanks.

How can I get a GSM Palm Centro UNLOCKED in the U.S.?

k8t — Sun, 24 Feb 2008 14:02:10 -0800

Palm Centro GSM Unlocked: how to get it in the U.S.? I love my Palm Centro so much. I use it on the Sprint network in the U.S. However, I am moving to GSM-land in a month and although I have a nice GSM phone, I'd love to have the brand-new GSM Palm Centro. (And it is not on eBay yet!) (And where I am going will certainly not have them available for purchase.)

AT&T is selling it in the U.S. and it is available in Europe. However, are these unlocked?

Any ideas on how I can get my greedy little paws on a second Centro?

How were cell phone calls completed from hijacked planes on 9-11?

Pastabagel — Fri, 30 Nov 2007 08:20:35 -0800

9-11 Technology Filter: I have never been able to even get signal on my Blackberry 8200 (GSM) within 10 seconds of liftoff, so how were cell phone calls completed from hijacked planes on 9-11? Specifically, given the prevailing handset, carrier, and tower technologies present in the Boston, NY, and DC metro and intervening areas at the time, and given the flight paths and altitudes of the hijacked planes, how were passengers able to complete cellphone calls to loved ones? On the radio this morning, I heard some conspiracy theorists posit that proof of the 9-11 hoax is that all the evidence of the hijackers comes from cell and AirFone calls from the planes. They claimed that one of the planes was not equipped with AirFones, but that nonetheless descriptions of that hijacking came from passengers calling loved ones and their own voice mails on their cell phones (I don't not remember which plane they claimed didn't have airphones). All I could find online that was remotely coherent was here but it is very light on the technical details which would seem to put this issue to rest conclusively.

Some my questions are as follows:

A. How was it possible to for passengers to complete these calls at high altitudes? Were phones and towers more powerful then? Did they use a different encoding scheme that was more robust? (Analog vs. Digital, CDMA vs. GSM, etc.) The more technical the response, the better.

B. Were any of these calls from passengers recorded? What about the infamous "Let's Roll" (or "let's roll it"?) call? Are the voice mails available online?

C. Is a map available of the flight paths of the four planes that (a) includes their altitude, and (b) includes tower locations from 2001 from the major wireless carriers?

D. Has anyone been able to complete a cell phone call from an aircraft at any time between a minute after takeoff and a minute prior to landing? What carrier and phone?

E. If you have ever worked near the top of a very tall building (i.e. much taller than surrounding buildings and far above the ground, i.e. Transamerica in SF, Sears Tower in Chicago, Empire State or WTC in NY, Petronas Towers, Taipei 101, etc), have you experienced poor service that was explained because of your floors height above the surrounding towers?

F. Do cell towers not broadcast or receive signals from above? I assumed that towers broadcast signal radially and would therefore be subject to the inverse square law. Am I wrong? Are towers in rural areas significantly higher and stronger than towers in urban areas? Why?

Sorry if this is too long or inappropriately formated for AskMe. There is very little I could find about this on the web, so any help would be appreciated, and as I said, the more technical, the better.

Do you use Virgin Mobile (in the U.S.)? Even better, do you use their Slice phone?

lorimer — Thu, 26 Jul 2007 05:49:22 -0800

Do you use Virgin Mobile (in the U.S.)? Even better, do you use their Slice phone? All its specs are fine for me; I'm hoping to hear how you like it (especially the sound quality of calls, since the reviews of that are mixed) and/or how you like using Virgin Mobile.

Can I buy a used or unlocked phone for my plan with Verizon, or is this a right given only to those blessed with GSM carriers?

Bengston — Thu, 15 Feb 2007 09:18:38 -0800

Can I buy a used or unlocked phone for my plan with Verizon, or is this a right given only to those blessed with GSM carriers? Ok, so I have tried to research this a bit and I still can't get a clear answer. There seems to be a lot of information online about all the different cell phone technologies, but no one seems ready to break it down simply and answer my question. Can I buy an unlocked phone for my plan with Verizon, and if so what are my limitations? I know I can't buy a GSM phone, but can I get some other kind? I recently slipped on the ice and split the phone I had before in half and its not time for me to get a hardware upgrade according to the contract so if I were to buy a new phone from Verizon I would have to pay full price and I am not about to do that.

VZW CDMA in China?

prettyboyfloyd — Sat, 09 Dec 2006 18:34:38 -0800

Will my Verizon CDMA 800 / 1900 phone work in China? Going next week. I have a US motorola e815 on Verizon's CDMA 800 / 1900 mobile network. (I assume 800/1900 is the wavelength(s)?) Can I buy a new sim card for this phone in China and use it while I'm in there to call back to the US? Should I even bother? I'll be in between beijing and guangzhou on a 2.5 week trip.)

If there is a way to get this phone to work, what's the best (ie, cheapest/most efficient) way? Do I need to unlock the phone first?

If this is all futile and I should just use one of those web phones over there then I guess that's okay :-(

(Also, may be going to Hong Kong too, any advice on a particular model brand-spankin-new gadget-o-licious phone that I can buy over there that will work on my verizon cdma network back here?)

Thanks!

How to change the number of times a Treo rings.

EnormousTalkingOnion — Thu, 27 Apr 2006 10:06:14 -0800

Anyone know how to change how many times a Verizon (so CDMA, not GSM) Treo 650 rings before it goes to voicemail? I can't find info on this on any of the relevant help sites or forums. Right now my phone rings for a solid 30 seconds before diverting the caller to voicemail and I want to shorten that. I found hash codes that work for GSM phones, but not Verizon. Anyone have the answer?

Fugly CDMA

glibhamdreck — Wed, 12 Oct 2005 19:28:27 -0800

I’d love a RAZR-cool phone, but I can’t find one for CDMA! I scoured phonescoop.com looking for design-first handsets. The Motorola V1150 and SLVR 8, Samsung Blade, and Nokia 6170 are all attractive—and all GSM. I guess the Nokia 6235 doesn’t hurt my eyes, but it’s still $250 USD for no real useful features for me. All this research has got me pining for some fancy foreign phones. Lastly, I’d gladly sacrifice aesthetics for some affordable WiFi.

Can anyone recommend a phone model I should consider?

Besides eBay, is there anywhere to shop for “unlocked” phones?

Is there anywhere to get Asian phones, and is it worth the trouble? (Apparently, South Korea has a CDMA version of the RAZR V3?)

Are any WiFi-enabled phones (that don’t cost more than some laptops!) available now?

Is it any trouble getting your carrier to reprogram competitors’ phones?

Is bluetooth worth the hype?

benjh — Thu, 04 Mar 2004 11:48:35 -0800

Is bluetooth worth the hype? I am in the process of changing cell carriers, and I am going from CDMA (Sprint) to GSM (T-Mobile) so I can't keep my phone. [more inside] I am torn between a Sony phone and a Samsung phone. The Sony has bluetooth, which I would think would be nice to geta wireless headset and sync to my PC, but the samsung is smaller, a little better on the interface and keys, but has no decent syncing capabilities.