Thetownend.com

The missus' 3G keeps losing all audio after she's been on a call for about 2 minutes.  She then has to hang up but if the person calls back, both people will be greeted with silence.  The phone then effectively switches itself on to silent and that's about it.  Switching the phone on and off a few times seems to resolve the issue. 

She used to be on 3.1.2 but I've downloaded iOS 4.0.1 and have done a reset (hold down home and sleep buttons until screen goes blank and Apple logo re-appears) but still no difference.  Time for a full factory settings restore? And if yes, anyone know of any decent program that backs up contacts, etc? Music and photos are sorted.

You sure she isn't accidentally muting the call? There is a problem with iOS 4 that causes the proximity sensors to not work properly, so it doesn't always deactivate the screen when you've got it up against your ear. Apple acknowledged the problem, not sure if it was fixed in 4.01 or not.

I'd try a full factory reset. I thought the iTunes backup and restore did everything (including contacts, calendar), it all comes back for me when I do it though that might be because I use a Mac and Mobile Me. If it doesn't on Windows, I'd just sync all the data to Outlook or Google or something similar before the reset then sync it all back again afterwards.

Though before a full factory reset it might be worth trying a "reset all settings" via the settings menu, which should reset everything to the original factory state but leave all your data intact. I say should and I take no responsibility if it fucks up.

Try Googling the problem, check some of the main iPhone forums as well for the problem.

She's probably holding it wrong. Or using it to make phone calls or something ridiculous like that. Whatever, it won't be Apple's fault. Heaven forfend.

As jonny says, it seems to be a common - although not acknowledged by Apple, hell no (<Bob Holt>There are no faults</Bob Holt>) - fault in iOS 4. The Reg had a couple of pieces about it which have links to forum threads complaining about the fault which may help. Assuming Apple haven't deleted the threads by now, of course.
http://www.theregister.co.uk/2010/06/28/iphone_proximity_sensor_complaints/
http://www.theregister.co.uk/2010/07/07/iphone_ear/

Paul looked over his chunky white faux-nhs glasses and dexterously tapped into his iPad carefully ensuring his Starbucks Doppalamochafrappicino was not shedding any of it's none-coffee like contents anywhere near his delightfully-enviable mid-brown moccasins.

"He'd read and helped enough of thetownend.com today," he told himself. He looked around seeing everyone bathed in envy. He gave a pleasing, if slightly conceited, porcelain aided smile as he placed his most recent Apple marketing exercise into his man-bag. As he did so, he ensured those nearby were treated to a glorious view and were able to marvel in something so advanced, so simple, but paradoxically so much like a massive phone, without the ability to phone.

He then purposefully rose to what felt like a statuesque 9'3" and looked down at the counter-cow, winking as he left. He knew he'd worked his magic. She knew he had an e-penis that had true clout, a might beyond mortals, a brilliance beyond imagining. He looked down at his Storm watch, thinking at what a fantastic "unbargain" he'd acquired from within the pages of the mildly readable, teen-mag, FHM. 

The time was 08:51, his office would be preparing for his 9:00 arrival. They always did, although his colleagues hid their delight well, he knew beneath a hard and hate covered exterior, that deep down all his fellow work-mites revelled in his arrival. He felt he was like the sunrise and they were the dew covered fields. He was like a leader, a prophet, a man beyond flesh, a man beyond talent, possessions, work, everything. He was new. Incredible, amazing. He was an iMan.

:D You're wasted on here. I wish even 10% of that bore any relation to reality (except the bit about the iPad, natch)

Please tell me you wrote that in Starbucks on your iMac and didn't crib it from elsewhere :)

 :Ride On Fatbury's Lovestick: Only the ginster wrappers recent posts can rival that, fucking genius!

Cheers Jonny.  I've googled the problem and been on the Apple discussion boards but can only find posts related to 4.X.  The problem's been happening since 3.1.2 so it's not something exclusive to 4.0.1. 

Going to try a full factory settings restore and take it from there. 

Of my own hand, but in Costa on my MacBook. :)

I'm truly iMpressed with that