Originally posted by: WayneTeK
Motorola T720 Cingular's Version
I just realized i'm more confused about this whole cell phone technology system than I previously though.
what is the difference between:
GPRS, CDMA, and GSM?
Also, my cell phone can't brwose the interent. The cell phone i have is listed in the link above.
Is there a reason why it can't surf the internet? Is it because my phone is a GSM modeL?
From what I hear, Cingular doesn't offer this service, internet browsing, at all...
GSM = TDMA (Time Divison) based protocol. Mandates other phone requirements as well (use of SIM for instance). Used in many foreign countries (it was after all developed by an European consortium), the EU recommended/required the carriers to use it, to promote greater interoperability. Carriers in the US: Cingular (some areas migrating from TDMA), T-Mobile, AT&T (also migrating from TDMA).
GPRS = GPRS (General Packet Radio System). Data (packet based) protocol for GSM networks. Generally improves data transfer performance over CSD (basically dialing up with your phone). I think this is also known as 2.5G.
CDMA = (Code Divison Multi Access). Qualcomm's baby. This is where they make their bank (patent licenses). Technically superior to GSM. All next generation networks (3G) will be based on a CDMA transport protocol (GSM will be using WCDMA, Wide CDMA). Carriers in the US: SprintPCS, Verizon.
CDMA vs GSM = With GDM/TDMA all callers get a fixed amount of time to transmit to the tower. If you have a theoritical 1Mb of bandwidth, and 100 callers, they each get 10Kb no matter what they're doing (there is a max number of users supported, as each requires a certain amount of bandwidth, these numbers are all pulled out of my ass). No matter what they're doing.. so if it's just dead air, and niether party is talk, that sound stream will compress really well, and the user's full allotment of bandwidth will not be used/needed.. but is unavailable to others. CDMA does not have this problem, and it is also asymetrical, mirroring conversational behavior (rarely do people all talk at once). Next generation CDMA networks can also deloyed side by side with current networks or overlaid. This allows for smooth transitions amongst the users. This is not possible for GSM carriers in their migration to 3G networks. This is evident in Sprint and Verizon's higher performing data options.
Even if you phone was an older GSM phone with out GPRS support, it could connect to the Internet using CSD (dial up). This would use your minutes, and you couldn't take call.. but if you have free minutes or whatever, it wouldn't be too bad.
But I have a T720 as well, and it supports both GPRS and CSD (you can tell by the icon that is 2nd to the left what mode you're in). If GPRS fails, it will swith to CSD. However, becuase those settings are all disabled in Cingular's version, you cannot explicity set which one to use. If it switch to CSD, it will not automatically switch back (bug), and to switch back you need to turn off the phone and turn it back on. You can also tell what mode you're in when you exit the browser (when you can use it). If it reports the number of bytes used, you're using GPRS (billed by the bytes). If it reports the number of minutes, you're using CSD (billed by the minute). Cingular does offer Internet browsing (at least in GSM areas), their GPRS plan is called Wireless Internet Express (I believe), and starts at $6.99/month. Before you can you the Internet from you phone you need to create an account at
http://www.mywirelesswindow.com/.
Another problem you may be facing on Cingular's version is finding the browser after you've remapped your shortcut/initial menu buttons. Cingular has removed the browser option from the "main menu", and thus can only be accessed if you map the browser to one of your shortcut/initial menu buttons. This should be found under Settings somewhere. By default, the browser is mapped to one of the buttons when the phone comes from Cingular.
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