A simple question

[ultranet]

Guys! what is difference between GSM and CDMA system?
thanks

 

[TheForce]

GSM stands for Global System for Multiple communications. It applies up to 8 conversations on a single frequency by slicing up the frequency spectrum.

CDMA is Code division Multiple Access. It assigns a code to each phone and uses a digital IDent to assign multiple conversations on a channel. CDMA has greater capacity to handle more conversations per channel frequency than GSM. It also can offer better fidelity because it does not slice up the voice spectrum. Plus CDMA doesn't have the background trash noise that some GSM conversations often can have on a busy channel. If the channel is not busy, GSM can sound as clean and quiet as CDMA.

CDMA was adapted by a couple of cell phone companies in the US and is considered more reliable in the US but only because of tower saturation, not system technology. However, more different countries have adopted GSM world wide so GSM is considered better, more convenient, if you travel abroad more.

All that said if you use the phone in one place you need to test each service to discover which works best for your use, ie the best reliability as measured in ability to effectively communicate. This would measure signal coverage, signal strength, consistency of signal connectivity (that is few or no dropped calls) and finally voice quality. The hardware technology for each has a range of quality so you can do well in both systems or poor depending on what phone you choose. I suggest read user reviews to find what works best.

In the US you have a choice, but if you live in another country, you may have only one, most likely GSM to use.

In the US- Sprint / Nextel and Verizon are CDMA

Cingular, T-Mobile are the GSM primary services.

These are the majors in the US for best coverage. There are other smaller and regional cell phone companies. I, personally, do not recommend them due to roaming costs and coverage outside your area.

Hope that about covers it.


Another difference is mainly due to hardware and it has to do with choice of phones- If you prefer to use one account and several different phones, the Services offering GSM allows an easy user swap of a SIM (System Information Module)card that will transfer your services from one phone to another. This is great in theory but often phones are locked so you may need to get the unlock codes to do the swap. Also, not all phones will swap cards with all other phones. Only similar phones can have card swap capability.
With CDMA, the swap process requires you to go on line or call the service center and transfer your IDENT number to the new phone. Then depending on capability, your new phone may also require a different service pack to make the paid services compatible. With Verizon the Ident swap can be made to any hardware device such as a cell phone to a PC card, but that would require a switch of services too.

Also, with CDMA- and world travel, Verizon, maybe Sprint too, has a deal where they will give you a phone that will work on your account if you contact them in advance, so not having a GSM phone in a GSM country is generally not an issue with Verizon.

Without getting into signal technicals, that about covers it.