iPhone 4S unable to turn off 3G?!

I have said this before on this thread... It is your network operator who decides when your phone switches between 2G and 3G as they configure all of the thresholds for reselection and handover. It is not up to the phone to decide this. It just does as it's told.

If you think you have identified an area of coverage where the phone is sticking to a 3G signal that is too poor to support service then you need to raise this with the network operator to change the reselection margins to more appropriate values.

Been there done that, and it's odd that it's only the 4S that's having this problem out of all the phones I've owned or the people I know aorund me.

The switch will still fix this problem for many many, people world wide.

**** my father's iPhone 4 has better signal all the time than my 4S even when they're right next to each other.

It's not the provider in the slightest, it's the phone itself.

"Once again, the option is not avaiable with the CDMA iPhone 4.

The iPhone 4S has a combination GSM/CDMA chip.

If it were technically possible with the combination chip, the option would be available with the 4S as is avaiable with the 3GS and iPhone 4 GSM running iOS 5."

Just because it is a combination chip doesn't mean this is impossible. Any sensible multi-purpose chip would have a whole raft of enable/disable options to turn features on and off. It would be a pretty useless chip if it lacked such basic config.

It is far more likely that because the chip in question evolved out of the one that was used in the CDMA iPhone 4, they used the CDMA iPhone 4 as the baseline to develop the 4S code.

Either they overlooked the addition of the toggle, or could not resolve the implications of adding it - with regard to confusing CDMA customers (to whom it would make no sense).

In a world phone the toggle would presumably be called "UMTS Enable" ??? Confusing for regular customers? Maybe they haven't decided on a nice way to label it yet.

If there is to be a UMTS toggle, should there be a full set of toggles for every type of system (GSM, UMTS, CDMA)?

I think Apple had a desire for an easy to use system which will work on any network without any messing about. It is just unfortunate that current 3G (UMTS) networks are in such a poor state that most folks seem to still need the disable 3G workaround. To make the point once again, these issues are network operator issues (with thresholds and with triggers to force your phone back to GSM when UMTS cell has no resources left).

If you are certain that your 4S sat next to a 4 (on same network and 3G enabled) performs significantly worse then I guess you are approaching Apple with this symptom - rather than asking fo the 3G toggle back, as this is a very different issue, and I would definitely agree with you if that is happening!

Apple would then need to take this up with Qualcomm.

Once again, if it were possible it would be available with the 4S as is available with the iPhone 3GS and iPhone 4 GSM running iOS 5. It isn't a matter of confusing CDMA customers (thanks for the laugh), and the option is not available with CDMA phones.

Can you name a phone with a combination CDMA/GSM chip that includes the option?

@jameswbuk - this is exactly what I was trying to say. I don't buy that it's not possible to toggle the state of each mode just because the control isn't present for it. Voice recognition wasn't present on a 3GS with IOS 3 or 4, but it was still possible and was made available in IOS 5. So much for the theory that things are not possible that aren't available from day one. And if Sprint and Verizon phones have to have their phones unlocked to use the GSM part of the chip, then there is certainly a way to lock the CDMA portion and re-introduce the ability to enable/disable 3G. Makes me think of the old 486 PC days when there was a turbo button on the towers. 🙂

The whole point is that disabling 3G functionality is sometimes still necessary, and it would be nice if Apple would find a way to make that possible with the 4GS. They have a lot of really smart engineers who have produced things that were much more technically difficult.

And again, this would be a moot point if carrier coverage was improved. Ideally we should never have to mess with network settings for the device to work, but that's just not today's reality.

And if Sprint and Verizon phones have to have their phones unlocked to use the GSM part of the chip, then there is certainly a way to lock the CDMA portion and re-introduce the ability to enable/disable 3G.

The GSM portion of the 4S does not need to be unlocked in order for a 4S activated with Sprint or Verizon to roam internationally with a GSM carrier. The GSM portion needs to be unlocked in order to use any GSM carrier's SIM card when traveling outside of the U.S. to avoid internatioanal roaming charges.

The whole point is that disabling 3G functionality is sometimes still necessary, and it would be nice if Apple would find a way to make that possible with the 4GS. They have a lot of really smart engineers who have produced things that were much more technically difficult.

I venture to say it is a chip limitation - the 4S includes a combination GSM/CDMA chip which allows a 4S that is activated with a CDMA carrier to roam internationally with a GSM carrier, and there is no such option with a CDMA phone - any CDMA phone. This has nothing whatsoever to do with unlocking the GSM portion of the phone to be used with any GSM carrier's SIM card.

That is very true, some GSM 3G networks don't have 2G networks to fall back on and a network carrier may chose to not include the API in the modem firmware of the phone.

An interesting note is that GSM networks can't and GSM phones have never had a toggle to switch from EDGE to GPRS, it is technically impossible and a comparable analogy as to why CDMA phones don't have the toggle from 3G to 2G, there is one radio for both CDMA/EVDO Rev. A and 1xRTT, just like there is one radio for EDGE/GPRS.

Thinking about this more....

Apple could easily provide this toggle in the device software, likely without much issue. But these issues really lie at the carrier level...both from the functionality perspective as well as the reason for it being necessary/desirable in the first place.

From the UI perspective, I picture something like a mode for "iPhone 3GS compatibility mode" or something along those lines. Throwing all the technical jargon at most end users goes against the whole Apple mantra of elegant simplicity. The function of this compatibility mode would only need to be available only to AT&T users (in the US at least), and would do exactly what we've discussed but might also disable other features, such as Siri, voice recognition, GPS or location service features that are data-heavy.

Of course, if the carriers were to agree to such a thing it would equate to waving a big white flag and admitting that their networks have issues preventing the device from reliably using the all of the iPhone's features. Hence, it will likely never happen. 🙂

More than likely it is a chip limitation with the combination GSM/CDMA chip. If it were easy or possible, the option would be available as is available with the 3GS and iPhone 4 GSM runnung iOS 5.

If you can provide a link to any other cell phone with a combination GSM/CDMA chip that includes the option to disable 3G when being used with a GSM carrier, I'd be interested in seeing it.

AT&T isn't the only GSM provider in the US. An unlocked iPhone can be used on any domestic GSM carrier providing compatibility.

transmogrification wrote:

AT&T isn't the only GSM provider in the US. An unlocked iPhone can be used on any domestic GSM carrier providing compatibility.

AT&T is the only supported GSM carrier for the iPhone in the U.S. Using the iPhone on other GSM carriers (the only other major one is TMobile) means you don't get 3G speeds, visual voicemail, FaceTime.

@Allam Sampson

It could very well be a hardware limitation. We don't know for sure, but just because other devices don't have the option does not mean it isn't possible. But the point is that exposing the functionality would also have business implications, which often outweigh technical benefits.

From a little Googling, I found a post where people have managed to disable CDMA, but it also disables voice calling (they referred to it as LTE-only). So perhaps the real fix is the rollout and support for LTE over EDGE and 3G. It makes the most sense for development and marketing efforts to be focused in this area instead of legacy technologies. Just one more reason we will never see the 3G off functionality rolled back into our iPhones.

Not true. GSM carrier H2O Wireless also officially supports the iPhone.

http://h2o-iphone.com/

I venture to say if this were possible, Apple would not have eliminated the option from the iPhone 4S when it is avaialble with the 3GS and iPhone 4 GSM running iOS 5. This was not removed by some whim or Apple randomly excluding or forgetting to include the option.

LTE-only - disabling CDMA is with an LTE compatible phone with Verizon's network. Verizon's CDMA network isn't going away anytime soon since they have rolled out their LTE network. One main reason for this is Verizon's LTE network will not be available everywhere just as their 3G CDMA network isn't available everywhere. All LTE compatible phones with Verizon's LTE network will be a combination LTE/CDMA phone for many years to come.

The same will apply with AT&T's network when AT&T rolls out their LTE network. AT&T's 3G/EDGE/GPRS network won't be going away anytime soon for the same reasons Verizon's CDMA network isn't going away anytime soon. All LTE compatible phones with AT&T's network will be a combination LTE/GSM phone to include 3G/EDGE/GPRS for many years to come.