Can't dial out or receive calls intermittently with 3GS and 3.1

Add me to the list of folks whose 3Gs sporadically has this problem following the 3.1 update - the phone won't send or receive text messages, incoming calls go straight to voicemail, and outgoing calls fail. Powering the phone off and back on will fix it, and whatever text messages were supposed to come in will come in properly timestamped. Wifi works just fine.

This wouldn't be such a huge issue if this wasn't my work phone and I wasn't on call 24/7. If our servers go down at 3am and my phone doesn't ring, my company won't care that there's a bug with the new update. They'll care that I didn't answer my phone. :P

Stopped by the Apple store today and of course they've never heard of this. Blamed it on the SIM card, and suggested I swap it out at AT&T. They also offered to order a new phone (this one's only a few weeks old). I declined on all counts as I'd already seen this thread and at this point am pretty convinced it's a problem with 3.1, not the phone. I'll wait a bit and see what happens and if there's a fix. I don't even know how to report a bug to Apple, or I would!

My boyfriend also has a 3Gs, hasn't updated to 3.0, and doesn't have this problem.

I've had this happen and can say with at least some confidence that it seems to be related to certain networks of certain types in certain areas.

For example, I've never had this problem around my home, but at one particular shopping mall despite full signal bars I can never get on the Internet using 3G and phone calls are flaky at best; both work much better on the EDGE network as does making and receiving calls.

Just at that mall; nowhere else in the area.

That's why I think it's AT&T, at least in large part.

I think you may be onto something, because I have only experienced the calling problems while I am at my work place, which so happens to have flakey 3G reception, one moment I'll have 3G an another moment I'll be on EDGE, but I do always have full bars, like you stated. However what strikes me a peculiar is that I have never experienced this problem until after I upgraded to 3.1, so I think it is a combination, between AT&T and 3.1.

But since going through my phone and resetting the network settings and then hard resetting the iPhone itself, I have not had the problem re arise.

Just an update and confirmation of the most recent posts.

My phone was okay all weekend at home where I have a reasonably good 3g signal.

I am back at the office today where most of the problems occurred. From here the signal is very bad. I am going to leave 3g turned off and see how things go today.

i have iphone 3G with 3.1 and same concern, but you guys notice after the reboot, your battery icon goes down to 20%!? when my phone acted up, i had 100% battery life, then i did a quick reboot, then it goes down to 20%.

My wife and I have new 3GS iPhones and have had the problem of not being able to call our or receive calls. It seems that all the WiFi functions work properly, but the phone does not work. We realized this today only when my mother-in-law called on another phone saying she could not contact us. When I did a hard reboot, I saw her voicemail. It seems that both my phone and my wife's went out in the same way this evening. She tried to call from the mall and could not. When we did a hard reset it came back too. We are using the 3.1 firmware. This is a real problem, because soon these are to be our only phones.

I have exactly the same problem since upgrading to 3.1, over the last several days waiting around for several important calls and then doing a hard reset and getting the voicemails from those calls. Also tried to make several calls and nothing happens until I do a hard reset and all is well for a while and then back to the same problem. I have tried restoring to a new phone with no change but I really think that this is an AT&T problem or perhaps an Apple firmware problem that the AT&T network can't cope with. Somebody needs to do something because we also don't have a landline and require reliable phone access 24/7!!!

Add me to the list as well. Apple support gave same guidance, first reset network, then get new SIM, then restore phone, then replace phone. Lots of steps, no solutions. If you rely on your phone for reliable communication, then the iPhone is not for you.

Since upgrading to 3.1, I'm having the same problems. Can't make/receive calls, texts won't go through and when trying to use the internet, get "Can't connect to the network. Make sure airplane mode is off." (It is). A hard reboot usually solves the problems but then it comes back a few hours later. I tried resetting to factory settings in iTunes last weekend, but that didn't solve the problem. In reading this thread, I guess I'll pay ATT a visit for a new SIM card and see if that helps.

This is my second iPhone. The first one had a faulty GPS. Right now, I'm regretting my decision to leave my former carrier for the buggy iPhone 3GS...

Count me in. iPhone 3G enters "zombie" mode since upgrading to 3.1. Never did it before the upgrade so unless the update physically broke something in the SIM or the phone (doubtful) then suspect it’s a S/W bug in 3.1. Don't text often, but the times I've tried haven't worked at all. Apple needs to fix this NOW!!!

I have also experienced this problem every day so far. This may be another symptom of the bad battery life problem that is also going on with 3.1 right now. I believe the reason for being unable to send or receive calls/data/texts is because for some reason, the baseband on the 3G radio is freezing. When I can't send or receive calls, etc, I notice that also my signal indicator is frozen as well (I always get 5 bars at my house, but I got home today and it was 3 bars, which I usually get around my school). I tried making a call, and of course, it was frozen up. The frozen baseband could very well be what's causing the problem with the bad battery life a lot of other 3GS users are experiencing. I notice that after about 30 minutes (or after a certain amount of time), the baseband reboots and the phone resumes normal operation, but this can take awhile.

Just had the problem again, after my phone was working for a few days. I have done following troubleshooting steps so far:
- reboot iPhone (fixes problem for a couple of hours)
- turning off 3G (fixes problem)
- restoring iPhone as new (does not fix problem)
- replacing iPhone at Apple store (does not fix problem)
- replacing SIM card (does not fix problem)

I am getting a little impatient with this, as I rely on being reachable via iPhone at all times.

count me in with the same problems. Also I find sometimes when I'm at home I'll make or take a phone call with full bars 3G and when I hang up I notice I'm on the "o" network and slowly it goes to the Edge and then 3G again.

Let me pile on -- I've been having the same problem for several weeks, although the periods when everything works after resetting the iphone appear to be becoming shorter. This is very frustrating, especially because I have plenty of bars showing. Ugh.

add me to this growing list. Today was the first day I noticed it having problems calling...it may have done this the other day but I just chalked it up to a blip. Today calls failed right and left, text messages hung on sending. I shut down/rebooted and all was fine for a few hours.

So I guess for a fix we should be asking for new Sim cards? see if that helps...this is all so confusing.