Q: iPhone 4S drops 3G, have to restart phone to get it back

Solution: turn off sim card PIN

I don't know that this is a universal solution.  My Sim Card Pin was turned off to begin with.

I tried turning it on, THEN turning it off, and this still didn't fix the problem.  The only temporary solution I've found is to toggle the Airplane mode on and then off.

Get the same issue in France. Only solution is to switch my iPhone 4S off then back on again. Any other tries (Airplane Mode, Manual Network Selection, ...) fail. When this happens overnight (which it always does) then my battery gets flat. I also have an iPhone 4 that never experienced the same issues...

Getting my iPhone 4S swapped for a new one at the Geneva Apple Store tonight - unsure that this will make any difference...

http://support.apple.com/kb/ht1316

I purchased iPhone 4G  7.10.2011  and I experienced 3G network loss  (I was not able to make phone calls, but the 3G mobile network work great and I was able to send SMS messages) every day, since I turn off the SIM PIN,  see the link above. Thereafter,  there have been no problems  in this week , no loss of 3G network, no problems with phone calls.  I am using Telia Sonera and ELISA/SAUNALAHTI 3G networks in Finland.

I am sorry to realize that Apple is not able to fix this problem.

Yes. Disable the SIM Card PIN lock:

http://support.apple.com/kb/ht1316

If this is not the permanent solution for you, try restore iOS and then disble SIM PIN lock.

The problem might be related to local operator settings and althouhg this prodecure was successfull for my 4S, it might not be working in other countries.

antti51 wrote:

 

Solution: turn off sim card PIN

I can confirm that "turn off sim card PIN" works fine for me!

turning off the card PIN only helps with the lockout, it doesn't really help with the dropped network connectivity. That still happens - it might just be that you normally don't notice because so far it didn't happen just when you tried to use it - it seems to come back after a while. But it leads to far too much activity of the phone and I guess that might be why affected iphones have that horrible standby time.

Same problem here in the US.  I either go flatline with bars or "No Service" and it stays that way until airplane mode trick is done.  Never had SIM lock on.  This phone is borderline useless as it is.

My brand new 4S 16GB also loses the signal or flatlines and will not make or receive calls or send text messages around 8-9 times a day.  I am getting most frustrated. 

Apple are sending me a new one but not until 14 November which is ages away.  No airplane toggle helps.  I shall try and turn off the sim pin and see what happens.  I have a horrid feeling that the one they send me will be the same.  I never had this with the 3GS.  I run my own business and really need to be contactable.

If I went back to my 3GS what happens to the info on the 2 phones?  The 3GS is not synched and not yet ios5 but I do not want to lose info on the faulty one.  I am also using Icloud.

Thanks for any help.

Turn off the pin code worked for me.

Telenor, Sweden.

Now I have 5 bars like I'm supposed to.

I have this problem too here in Denmark. Old iPhone 4 says 3 bars on 3G, new iPhone 4S says 1-2 bars on EDGE! ***! Tried with my wifes new iPhone 4S too - the same.

I already turned pin off.

When I lay my iPhone 4 on the table (has a subwoofer under the table), there's no noice ... but when I lay my iPhone 4S on the table, all **** breaks loose and the subwoofer makes lotta noice. It's like the iPhone 4S is constantly talking to cell antennas. This is also affecting batterylife.

Hmmmm ... another antenna gate?  

My hype for Apple is strongly fading - sure they make great UIs, but they are getting worse in making phones.

Well, since I wrote on here and turned off the SIM pin, I am scared to say, incase it doesn't last, but I have had full signal and not had to restart once!!

I bet now I have written this it will play up!!

...and also it is now 4.40 pm and my battery life charged 100% this morning at 7am still says  76%!!!!  normally much lower than this, and I have used it for a long call, texting and surfed the net!  

I have same issue and set pinn off dont help me nothing. Only way get signal work is get airplane mode, but that is not good idea because that happend 10-20 times days.

Disabling PIN on SIM solved all my NO SERVICE problems. I use Telia in Sweden. I live in an area with bad coverage and did loose service before after a few minutes when moving indoors with phone in idle.  While entering the general/about section of the preferences I was informed about, and accepted downloading, new operator settings. Do not know if it is part of the solution?