I am on Orange UK and I have been having the very same issue.
When I have called Orange in the past, they have blamed it on transmitter work preparing for sharing 3G signal with T Mobile and gave me some end dates for when this work should finish in Cardiff (around 22nd March).
I have been consistently having problems since and rang again last week. This time, I spoke to an Orange iPhone specialist who said there seems to be an issue on iPhone 4 at the moment where if you have been connecting to the internet, the phone will somehow hold onto a data connection and not allow any voice calls or texts through. Making an outward call breaks the data connection and then the phone is available again. He also said quitting any apps should help but I found you still need to make a call out and besides, even if I use no apps all day, my e-mail pushing through still seems to cause the problem.
One symptom is that you suddenly get texts and voicemail messages through once you make a call. I upgraded to 4.3.1 last week hoping this would resolve the issue but it hasn't.
Bizarrely, this even seems to be the case if I am using my home wifi and not 3G
My brother and sister both have iPhone 4 (iOS 4.3.1) on Orange but in Aberystwyth and they have not had this issue. Interestingly, I have just spent a long weekend there and had no issues. I came back to Cardiff last night and I'm having the problem again. So I can't work out who I should be chasing; Orange or Apple?
Has anyone managed to shed any light on the issue yet?
I have good 3G signal but the transmitter work in Cardiff could cause a 'problematic' 3G signal.
However, when you say missed calls, you mean the phone will miss them if it switches between 3G and EDGE at the time of a call? How about SMS? Why would these massages not deliver until an outward call is made?
SMSs should deliver sooner or later in the next minute or so regardless of reception. Maybe SMS issues could be different and I suspect them to be tied to possible provider wrong settings.
Regarding the switching between GPRS/edge and 3G, this could be going on continuously when not in a middle of a call. That will drain you battery and cause lots of missed calls (inability for the other party to reach you). When a cellphone falls from 3G to GPRS/edge during a call, it will usually NOT switch to 3G again until the call is over, so the call will go on as expected.
If your iPhone is switching between 3G and GPRS/egde continuously, you'll probably be able to see the 3G icon come and go every 10 to 30 seconds. However, problematic 3G reception could fool the iPhone that all is good, and fail to fall back to GPRS/edge.
I would suggest turning 3G off and see how it goes for a couple of days.
Right, I have been off 3G since yesterday afternoon and I still get the same problem. In fact it was worse this morning; normally if I make a call out, I am then contactable but I quit all apps, made a successful outward call but then I couldn't call my iPhone from my landline at work. I was only able to make a call to my iPhone after I switched cellular data off altogether.
While writing this, I've just carried out another test; Having successfully called the iPhone from a landline, I switched cellular data back on but I haven't run any apps. I tried ringing from landline again but it goes to 'unavailable message' again. I swith cellular data off and it receives calls straight away.
It's as if the iPhone is holding onto it's data connection and not releasing it for Voice Calls or SMS.
I'm still none the wiser as to whether this is an iPhone 4 issue or a network issue (Orange UK).
Anybody (aside from OP) got the same problem or a suggestion as to what to try next?
When you have data switched ON, and you're NOT on 3G, then whenever there is data traffic on your device, your iPhone is actually not available. When you are connected through a well-working 3G service, the iPhone can handle voice and data at the same time.
That said, it seems to me that there's some application that's been downloading stuff, hence keeping your GPRS/edge connection active all the time. This is definitely NOT a normal behavior for the iPhone. I suggest you switch off / on your device and try again calling your mobile number from your landline, with 3G turned OFF, WiFi turned OFF and data turned ON, just to make sure. Do not launch ANY applications until you get some results.
There are certain applications that actually keep data connections alive, Skype being one of them.
I have been having similar problems over the past few months. I live and work in the CF11 area and have an iPhone 3.
I sometimes dont receive calls ( caller gets the unavailable message )and sometimes dont receive text messages for over an hour when i may then receive numerous texts send by numerous senders in one short time.
I have contacted Three (my provider) who i have been with since they started out. They assured me that they would have their Network Specialist contact me with 24 to 48 hours. I also told them that I would seek another provider next week if the issue was not resolved.
I expressly told them how much I relied on my phone for business and how much I seemingly have already lost. (My clients had subsequently contacted me and told me how they have had problems getting hold of me).
I have tried all the suggested fixes and resets possible and nothing seems to resolve the problem.
My partner who has an iPhone 4 with Three does not have any of these problems. She however cant pick up wifi hotspots very well. ( Thats another story )
Okay, so here's what I have tried this afternoon; about two hours ago, I shut down and rebooted iPhone 4. I rang it from land line to establish that it works.
3G is OFF but cellular data is ON. I have used NO APPS (aside from 'Phone' to receive the test call).
As I suspected, phone has been suspiciously quiet so after some meetings, I just tried to call it from my land line and I get the "The person you are calling is not available" message.
The only thing that will have used any data is Push mail (I can see that 1 email has arrived but I haven't actually opened the app to read it).
I just switched cellular data OFF and redialled from landline and it rings instantly.
So at the moment, it seems that I have an iPhone 4 which can either be used as a connected PDA or purely as a dumb phone. Not good.
Well this muddles the issue for me as to whether it's an iPhone issue or a network issue, as I have an iPhone 4 on Orange and you have an iPhone 3 on Three!
I work in CF5 mostly, sometimes in CF10 and CF14 and live in a different CF postcode but it's the same in both areas.
The one thing that makes me suspicious about network is that I didn't have any problems while in SY23 (Aberystwyth) over the weekend.
Maybe I'll just contact Orange, Apple and Carphone Warehouse to see who can help resolve the issue first!
One last little test I did; I changed the settings for Mail from PUSH to FETCH and set the interval to MANUALLY. Once again, 3G is OFF and Cellular Data is ON
Closed down the 'Phone' and 'Settings' Apps and rebooted phone. Rang it as soon as it booted and it received the call. Left it five minutes and then rang again (having not touched it). I get the "Not available" message once again. Switch Cellular data off and ring again, the call comes through.
So it seems even if nothing else has used the data connection, just the very fact that it is active seems to cause the problem.
I'm sorry if I have hijacked this thread but I assume OP has the same problem.
Anybody have further thoughts on isolating the problem?
You could next download DataMan (free version) and check if while the iPhone is idle there's significant data coming in from the cell network. Launch the app, quit it, leave the iPhone for like half an hour and then check with DataMan again. If you don't see a figure over 200KB, something's wrong with the network, you should contact the provider and tell them to reset your line or something...
Quick update on this. Today, I thought about leaving Cellular data on but shutting down any notifications that I didn't really need.
So, I went through the list leaving things like Whatsapp, eBay, etc and switching notifications off for apps like games, Bump, Star Walk, etc.
I then ran just about every internet hogging app I have (Skype, MSN Messenger, Twitter, AV Forums, Safari, Whatsapp, etc.) and started ringing my phone. It rang through every time, even while in the middle of a Skype call (as it used to).
I then switched all notifications back on to try and isolate the problem app by switching notifications off one by one (should have done this in the first place!). However, I left all the notifications on, kept all the apps running and have had 3G data on all day. I have tried calling regularly throughout the day from my office landline and been receiving calls and texts all day.
I don't want to say that it's fixed (will see if it works for a week or so before I say that) but it's the most problem free day I've had since I first noticed the problem.
So, either a network issue has been resolved, or switching notifications off and then back on has done something to fix the problem.
Worth a try if anyone else still having problems.