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SilentLoner

macrumors 65816
Original poster
Dec 29, 2007
1,065
6
When you switch between the two. Does the CDMA chip activate and switch on then? Do you need the nano sim if you want to use it for just 3G/2G. I'm on about the iPhone 5.
 
Nano SIM is required at all times as it is so a C-SIM. Removing the SIM, will remove all service from your phone just like a normal GSM phone.

But sounds like you got the rest right. CDMA is always running for voice. LTE for data only.
 
Nano SIM is required at all times as it is so a C-SIM. Removing the SIM, will remove all service from your phone just like a normal GSM phone.

But sounds like you got the rest right. CDMA is always running for voice. LTE for data only.

That's cool. I find the differences fascinating. What is different between a c-sim and sim?
 
When you switch between the two. Does the CDMA chip activate and switch on then? Do you need the nano sim if you want to use it for just 3G/2G. I'm on about the iPhone 5.

you ever notice when you switch to LTE it stalls for a little then the status bar says LTE after 5-50 seconds(depends on your area)? That's because it is turning on the lte signal since it is a seperate chip and then finding a signal strong enough to replace the 3g one.
 
No, there's no "separate chip". the i5 uses Qualcomm's single radio chip for this device, hence the good battery life compared to many other devices that have to use separate radio chips.
 
No, there's no "separate chip". the i5 uses Qualcomm's single radio chip for this device, hence the good battery life compared to many other devices that have to use separate radio chips.

There is a chip in the iPhone 5 for LTE. MDM9615M modem is the name of it
 
That's cool. I find the differences fascinating. What is different between a c-sim and sim?

C-SIM is a SIM card that is for CDMA, it still is compatible with GSM, for when you're roaming. In essence it is a normal GSM SIM with extensions to allow for usage of the SIM on CDMA.
 
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