Ok, even though I suspect a lock coming, I must correct about a million things from the first post in order that people don't walk away with all the wrong information. It just hurts my head.
There were 4 wireless protocols (in the US):
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Analog (AMPS) - static, but you wouldn't "drop" a call, it'd go to static long before... the benefit, keep driving or turn around and you conversation *might* resume. (800 mhz)
TDMA - The next protocol to come along in the US. Basically, your message gets chopped into a bunch of bits and pieces, compressed, and they get shuffled into a queue in midair and sent to the tower. This was the first digital technology to come along... think ATT and Babybell, you know, back when those were basically the only options. (800 mhz for old style digital/ 1900 mhz for PCS)
CDMA - Old technology (WWII), but put to new use when PrimeCo and Sprint built out their networks, mostly using Qualcomm parts (they had the rights to cdmaOne). Your voice is chopped up, duplicated in slightly different bands, and blasted shotgun-style at the tower. The tower pieces it together, or, if it can't you get the digital worble sound as it does it's best. When too many people are on a cell, best signal wins, loser's call is dropped. Thus it's VERY important to build out a dense network to support the number of customers and maintain good service. ( 800mhz analog, 900mhz PCS (outside US), 1900mhz PCS)
GSM - While GSM qualifies as it's own technology, it's more of "windows on top of DOS" kind of setup. It was set up as bunch of features on top of a TDMA network working in a higher frequency. Due to frequency differences between the US and the rest of the world (as well as no established roaming contracts) you could not roam using a US GSM phone in Europe or vice versa. Now there are triband phone which allow roaming. (900mhz and 1900mhz in Europe, 1800 mhz in US).
Cell phones are divided into 3 (not really, as you'll see) generations:
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1G - Analog and digital (non-pcs), ala ATT and Babybell service when a phone could just dial and receive calls.
2G - TDMA PCS, CDMA PCS, and GSM - You want to send messages or use your cellular as a modem (albeit slowly), you got it. PCS is here.
3G - The once mythical couldn't be decided on standard. Can't decide.. well, let's throw out a couple options but make it 2 standards instead. Kind of a temporary one, and a longer term goal. Introducing cdma2000 (cdma with tweaked features) and w-cdma (wideband cdma... wideband meaning fatter pipe meaning more features). Also, cdma2000 has several different tiers of speeds. The first tier (1x) only allows at most 144kps throughput. This resembles a 2.5G protocol (see below) more than a 3G.
But... lots of carriers decided 3G was expensive and didn't think the features needing all that bandwidth had really been invented yet or that consumers would pay enough to cover costs of implementing them. They wanted a shorter term solution. Welcome to the fractional number generation, 2.5G. As if being an outcast because of it's decimal wasn't enough, it actually ended up being even more of a black sheep by having multiple personalities.
2.5G protocols -
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CDMAone - A revised CDMA with more bandthwidth, better compression, more reliability, and just different enough from cdma2000 to make CDMA phone in North America not work with those in Europe and Japan. We gotta be different... it's our claim to fame. This is what Sprint and Verizon are using. When they want to jump to 3G, they go straight to cdma2000. Easy enough.
GSM with GPRS - GSM with General Packet Radio Service. GPRS can send data at speeds ranging from 9.6 kpbs to 57.6 kpbs by combining three to six voice channels in the TDMA system. So, you can browse the internet about as fast as you can on dial-up. YAH! This protocol got a big boost when ATT decided to jump to it instead of going to CDMAone as a go-between to 3G. Cingular and any existing GSM carriers (Voicestream/T-Mobile) also are migrating along this path. Here's where things get a bit tricky. In order to go to 3G, GSM carriers are moving to an intermediate 3G technology before making the jump to W-CDMA. EDGE (Enhanced Data rate for GSM Evolution) is an evolutionary 3G technology based on existing GSM which will allow 384kbps data over a TDMA connection (once they work out a few kinks in quality). While EDGE is considered 3G, it's not a worldwide 3G standard, meaning it isn't really an approved final destination... thus the eventual leap to W-CDMA.
What this means to you:
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* The 2.5G (CDMA2000 1X and GSM/GPRS) networks are not fully built out. In other words... your fancy internet access feature isn't going to work everywhere yet. Check with your local carriers.
* Reception depends upon where you use your phone and where the towers are in relation to you... not which carrier you have. Every carrier has their problem areas (dropped calls, etc) and dead spots. They all basically are using the same frequency range (1800-1900 mhz) so one doesn't work indoors better than another. Only for you, only for that building, in your city, with your crappy phone with the antenna kinked just a little bit at the tip. Everyone's experience will be different (even using the same phone model and carrier standing next to each other). It's the nature of the business and technology... YMMV.
* Verizon and Sprint are almost identical in frequency and technology. The only difference is where the towers are, how well they're tuned, and which model of phone they're carrying and whether or not your region of that carrier has updated to 3G. Each carrier has different penetration rates for different areas. One may work better for you in your city, but again, that's only for you. Not to say "Verizon is better than sprint because of" some nonsense about their frequency.
* ATT and Cingular are virutally the same as each other, as well. Read the previous paragraph and instead substitute these names for the previous. Also, in some ways they are almost more alike than Verizon and Sprint because ATT and Cingular carry a lot more ofthe same phone models than the CDMA carriers do. If you bars read high on ATT on a certain phone and you always get dropped, chances are if you have the phone reprogrammed for Cingular and stand in an area with a similar tower configuration, your signal strenth will read high and your call will still drop. There's no magical mystical difference in how one carrier implements the same technology over the other. It all comes down to tower placement and tuning (and de-tuning in the case of interference with other radio equipment located nearby).
* Your satisfaction is probably going to depend a lot on how well you chose your plan and phone and whether it fits your needs more than what carrier you have (unless one of the carriers is neglegent in building out in your area).
* While the carriers all run different prices for phones and each carrier may have it at different prices in different markets or even through different retailers, it has a lot less to do with how much kickback that carrier gets and more to do with logistics. If a retailer can sell a lot of phones for a particular carrier, that carrier will cut the retailer a deal on the price of the phone in order to boost the subscriber base. If a particular phone model isn't selling well, a carrier might offer a retailer a discount in order to liquidate the model as well as draw more subscribers. Pretty much everbody has a contracted agreement period for a reason... they don't make money off you on the phone... it's the service they want you coughing up money on with no hope of escape. Not only that, they're not making as much money off you as they can on the service due to their own price wars. So now they want you to buy added features, especially ones that cost them relatively nothing and you lots. That's the beauty of SMS, checking stock quotes, etc. Very little bandwidth used, and they can get a premium for it. The next best thing is data services, though since they use more bandwidth, are not as profitable if they don't charge you handsomely for it. And once you've got it, you want it faster, making them spend the money on the next infrastucture upgrade to next generation service. So they do charge you fairly handsomely for it.
* GSM will not be obsolete for quite a while. GSM consists of 2G GSM, the new GSM/GPRS, and then EDGE. You can expect this to reach easily to 2006. Even so, W-CDMA incorporated a lot of the benefits of GSM and so GSM will live long into the future.
And to wrap it up, I'll post a series of progressions on the technology each carrier used/uses/will use to make it simpler... the key to reading this is used -> uses -> will use
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ATT - Analog 800mhz -> TDMA 800mhz (digital)-> TDMA 1900mhz PCS -> GSM/GPRS -> EGDE (GSM) -> W-CDMA
BabyBell/Cingular - Analog 800mhz -> TDMA 800mhz (digital)-> TDMA 1900mhz PCS -> GSM/GPRS -> EGDE (GSM) -> W-CDMA
(for those of you who live in the areas where Cingular absorbed companies like "Bellsouth PCS (GSM)" refer to the Voicestream/Omnipoint/Aerial/other GSM progression below
VoiceStream/Omnipoint/Aerial/T-Mobile/other GSM -> GSM (1800 mhz) -> GSM/GPRS -> EDGE -> W-CDMA
Verizon (PrimeCo) -> CDMA (800mhz) -> CDMA PCS (1900 mhz) -> CDMAone -> CDMA2000 -> W-CDMA
Sprint (seperated out in edit because of it's digital start and slightly different technical path from PrimeCo) - CDMA PCS (1900 mhz) -> CDMAone -> CDMA2000 1xRTT (144kbps data theoretical, Sprint's throughput about 60-70kbps) -> CDMA2000 1xEV (2Mbps data) -> W-CDMA
Phew!
I would have let this post drop as directed, but leaving dribble out there for who knows how many people to see and base important decisions on made my brain hurt. Plus, it kept rising to the top on off topic info about Florida's lovely methane generating mountains known as trash dumps. My favorite is in Port St. Lucie where they proudly carve the name of the city into the grass on the side of it visible from I-95.
editted to correct Sprints current position and migration path to 3G