Will an unlocked iPhone 4S work with both CDMA and GSM SIM cards?

Hey varun0809,

It sounds like you have a question about the specifications of your specific model of iPhone 4s. Here is an article for you that should be able to help you answer these questions:

iPhone 4S - Technical Specifications

http://support.apple.com/kb/sp643

Cellular and Wireless

• World phone
• UMTS/HSDPA/HSUPA (850, 900, 1900, 2100 MHz);
  GSM/EDGE (850, 900, 1800, 1900 MHz)
• CDMA EV-DO Rev. A (800, 1900 MHz)3
• 802.11b/g/n Wi-Fi (802.11n 2.4GHz only)
• Bluetooth 4.0 wireless technology

1. 1GB = 1 billion bytes; actual formatted capacity less.
2. Actual size and weight vary by configuration and manufacturing process.
3. CDMA available only if iPhone 4S is sold and activated for use on a CDMA network.
4. All battery claims depend on network configuration and many other factors; actual results will vary. Battery has limited recharge cycles and may eventually need to be replaced by Apple service provider. Battery life and charge cycles vary by use and settings. See www.apple.com/batteries and www.apple.com/iphone/battery for more information.
5. Wireless broadband recommended; fees may apply

Some features, applications, and services are not available in all areas. See your carrier for details. Application availability and pricing are subject to change.

Thanks for using the Apple Support Communities!

Cheers,

Braden

varun0809 wrote:

I was using the iPhone 4S with a GSM sim card all these years here in India and would like to switch to a CDMA carrier.

Does the phone work with both SIM cards? Or is there a separate model which works with CDMA?

There is actually no such thing as a CDMA SIM card. Most CDMA carriers require that you purchase a phone that is intended for use on their network. Have you contacted the CDMA carrier to which you would like to switch and asked them?

varun0809 wrote:

I had heard about CDMA having a better quality than GSM, but nevermind....thanks anyway!

What's more important is the provider's coverage: number and placement of towers.

Meg, This is right up your alley.

What I know about iPad:

A Verizon iPad is interchangeable with other networks. Just pop in the appropriate SIM card. IPads are not locked.

A non-Verizon GSM iPad (ATT, T-Mobile) is NOT compatible with the Verizon Network because Verizon performs and requires a separate Verizon IMEI registration when you buy it,

Therefore, only a Verizon iPad works on all carriers (except another CDMA network, e.g. Sprint).

What i think about iPhone 5 or 6:

An unlocked GSM iPhone 5 or 6 (ATT, T-Mobile) works on Verizon. Just pop in the appropriate SIM card.

Verizon states their is no unlock for their iPhone 5 or 6.

Question:

Will a Verizon iPhone 5 or 6 with no contract work on another network anyway?

If not, is there any way to unlock it?

Does that mean you need to purchase an unlockable GSM iPhone 5 or 6 for complete portability?

chasblue wrote:

What i think about iPhone 5 or 6:

An unlocked GSM iPhone 5 or 6 (ATT, T-Mobile) works on Verizon. Just pop in the appropriate SIM card.

Verizon states their is no unlock for their iPhone 5 or 6.

Does that mean you need to purchase an unlockable GSM iPhone 5 or 6 for complete portability?

No, an unlocked GSM iPhone 5 or 6 won't work on Verizon. One person claimed they got a TMobile iPhone 6 to work on Verizon with an already activated SIM but I'm not sure I believe it. Verizon still uses CDMA for voice calling. The IMEI needs to be in Verizon's equipment database.

Question:

Will a Verizon iPhone 5 or 6 with no contract work on another network anyway?

If not, is there any way to unlock it?

Does that mean you need to purchase an unlockable GSM iPhone 5 or 6 for complete portability?

Yes, a Verizon iPhone 5 or 6 is unlocked and will work on other GSM/4G LTE networks. It will not work on Sprint's CDMA/4G LTE network.

I put my ATT i5 SIM into my Verizon i5, it didn't work. Does Verizon have to "release" the phone from defaulting to CDMA? That is, is the phone defaulting to CDMA because it is an active account?

If the phone is currently active on Verizon, that might be the cause of your problem. Don't know for sure as I've never had any reason to try to use AT&T.