Q: iPhone 4S dropping network and data at random

cure is 128k SIM!

128k may cure

but my operator does not have sim cards 128k

I completed a full reset on Friday evening and then set it up as a "new phone" declining to use the online backup. (I also deleted the icloud backup after this and re-created it)

As of 48 hours in the phone has been performing without any problems. My Cellular network connection has been stable with data turned on, and i have not seen any unexpected drops to "searching" aside from my own tinkering with the network settings.

Today is the first time since Friday i've been outside of my home wifi for a prolonged period but thus far (3 hours in) the 3G and Network connection seem solid.

Also one other plus side to the reset has been that battery life thus far does appear to have improved slightly. Example being that last week watching 40 mins video was taking 100% Battery down to 82%, this morning it went from 100% to 95%

This time around i've declined "push" notifications from most apps installed wheras previously i had authorised this. If this was the cause of the battery drain i'm significantly happier with it this way.

I'll continue to monitor and post updates here on the network dropping, as if it is phone defect it's likely to happen again.

i have 32gb iphone 4s, prior to the update i used to receive the "invalid sim" message every now and then, but i used to use my phone with almost every function on (siri, location, auto time, cell data, etc.) without any problems...

after i have updated my phone to ios 5.0.1 on 11.11.11, i could only connect to my carrier when i tried to call someone up, fail and after receiving the "no service" followed by "searching" messages, where i could only make a couple of calls and then experience the same thing over and over again... i couldn't even connect to cell data may it be edge or 3g...

after searching for a solution i have seen here that some people got rid of the problem by simply replacing their sim cards, i gave it a try and voila, it works... i have specifically asked for a 128 k sim card, which did the trick, i have been using my phone and cell data for the past 4 hours without any interruptions and somehow it seems that the reception got better as well...

btw, i am using the phone with again, every function on both to test the connection and battery issues...

thanks to everyone who left a feedback...

I´have the 128k sim in my 4s but the problems are still the same.

Very strange how it will work for some and not for others:-(

I changed my cutting microsim to original (not cutting) microsim 64K and don't have any problem with signal for 2 hours already

@nesse10

How can you tell your SIM is 128k? I talked to Tele2 today and they actually told me it wasn't the problem and that they used 32k SIM-card.

i tried all kinds of SIMs...32kb, 64kb and even 128kb...it doesnt work!

I even switched providers (from Globe Telecom to SMART Telecommunications, both in the Philippines) and the problem persists - so its definitely NOT the SIM cards :S

Either iOS5.0.1 is messed up or something is broken with our hardware...(i surely hope its just the software..)

btw similar to "Wkuratov", after a reset i'm able to RECEIVE sms and calls, as often as i like, but im not able to MAKE calls / SEND sms - as soon as i try this, the signal goes down and @#$%^&*....

I'm running out of ideas...:(

@hejo82

That´s really strange

I talked with somebody att support, he put me on hold to ask a technician.

He came back to me with the anwer that they use 128k

Will call them again to see if I get a different answer.

Good thing you mentioned this

hi, i don't mean to bother everyone with my story again, but the sim card i've obtained today (well, of course the actual part is in my phone) can be seen below, and it really does work... i don't know, maybe it's a carrier specific issue, but my old one gave me a ton of headaches...

i've checked the iphone 4s manual as well and it does not state any kind of sim cards at all, just "sim"...

i also found the below explanation from http://www.justaskgemalto.com:

SIM cards (Subscriber Identity Module) are used to communicate on GSM networks. With the introduction of UMTS or 3G, it's highly recommended to use a USIM card to access UMTS network. Although it's possible to access it with a simple SIM card, the USIM have many advantages as compared to the SIM:

• A USIM is a tiny computer which is able to handle several mini applications, for instance a contactless e-purse for the subway, a local service portal giving you access to your phone bill, etc;

• A 3G (UMTS) handset equipped with a USIM card can be used to make video calls, assuming the calling area is covered by a 3G network;

• Regarding security, a new algorithm is integrated (it's derived from recent researches in cryptology). It allows to protect you from unauthorized access to your phone line, and therefore to be charged with fraudulent calls on your bill;

• Your calls and data exchanges are encrypted using keys computed by the USIM, and these keys are stronger than those provided by SIMs.

• The phonebook is much bigger on the USIM, allowing thousands of contacts (instead of a maximum of 255 in a SIM). Each USIM contact is also richer, for instance it can contain email addresses, a second or third phone number, etc;

• Contacts in the USIM are stored much more securely on the USIM as compared to using the phone memory.

the exact address of the above text: http://www.justaskgemalto.com/en/communicating/tips/what-difference-between-sim- and-usim-cards

@hejo82

Just called back to Tele2 and talked to support

Guess what, Here in Sweden we only use 32k in mobile phones. the 64k sim card is for only 4g mobile modem!!!!

And why that other jerk at support would give me false info is a mystery, the guy at support was going to investigate further why I have been told this as there has been created a logg in this matter and he could actually see that i have received wrong info...

Frustration is the least I´m feeling now!!!

Nesse10,

I also have Tele2.  I had problems with a brand new 4s (using a brand new sim).  I tried another sim card, and I still had the problem:

Phone showed 5 bars/connection, but when I tried to make a phone call, the bars went to down to none, to "Searching" back to to 5 and I could make one call.

I did the no pin-sim - didn't work

Restore to new phone - didn't work

Tried turning off different settings - didn't work

I finally got tired and took the phone back to Media Markt.  They sent the phone to Tele2, and they exchanged it for a new one. I put in the same sim I was using on the "problem 4s" and the new one works fine.  I also upgraded to 5.0.1 without any issues.  I have been using it for 3 days now.

@nesse10

Great work sorting that out. Thank you for confiming this! What now then? Seems like we are pretty stuck in the land of incompetens (Tele2). No status what so ever. Hope Apple is on to something, that seems like the only rescue atm.

I got a new SIM card today. Now it works w/o any problems!

So it's definately a software problem with 5.0.1

Had these same problems since Friday update to 5.0.1 on my 4S.

I've cut out my original SIM card from the standard-size SIM, and it worked great for a week under 5.0, until the update. Afterwards all **** broke loose (Invalid SIM, dropped network, Call failed, etc).

Today I've got a "real" MicroSIM, from a different operator, and so far it all works great without any problems.

The card is just like the one displayed on top of page 18. Don't know whether it's 128k or not though.