Disabling EDGE might not always help since removing the AP does not actually disable the service.
The iphone WILL try to startup a connection and fail to do so due to not having the settings, but calls might still get dropped during that time...
Another theory (that's mine btw ) is that during sleep mode the iphone goes into low-power GSM and drops your signal...how strong is your signal when the phone is awake?
I am having a similar problem with my iPhone.
From what was indicated above, it appears that power to the communications board is interrupted when the phone goes to sleep. This interruption may not occur if the phone is plugged into a power source. If this is truly the case, then no amount of relocking/unlocking is going to help because it is NOT a commboard issue. It sounds more like a logic board issue. I also doubt it's software because - logically - a restore should solve that.
I have a spare (broken commboard) iPhone lying around. I will attempt to swap the logic boards and see what happens. Don't hold your collective breaths because I am not sure when I'll get down to it, or if it will even work.
I have to remind you, that if iPod launched then iPhone ring too. So I doubt of it have something to do with power. And what the difference between locked sleeping iPhone and unlocked sleeping iPhone? But if it isn't locked then it rings.
I am not sure if I understand you, TapaH.
I am assuming that the commboard is functioning properly if the phone works when it's not sleeping. My assumption is that when the phone goes to sleep while running solely on battery power, the logic board stops supplying the commboard with the necessary juice to keep it running.
I have noticed that when I wake the phone from sleep (under battery power), the signal strength is invariably at zero. It will then briefly show "No Service", then regain full strength, register network, etc. When it's plugged into a power source, waking the phone from sleep reveals full signal strength without any interruption.
On another hand, it could still be a commboard problem if it doesn't like low-power scenarios. I am hoping it's not a commboard issue.
Anyone else with theories?
The proof that the signal remains is that I always have the missed call messages after I awake the phone, so the commboard received and registered the call...
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Wait a few hours. My friend said me that he had fixed this bug by software. I'll get my phone back and check, then I'll tell if it's true.