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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > iPhone, iPad & iPod > iPhone cell radio interference with LCD monitors

iPhone cell radio interference with LCD monitors
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Fresh-Faced Recruit
Join Date: Nov 2007
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Dec 3, 2007, 02:29 PM
I suspect that this is a general cell/monitor question rather than one specific to iPhone, but I wanted to see if others had experienced this same interference issue with their iPhones.

I have two Dell 2000FP LCD monitors running 1600x1200 DVI-D off of a dual-DVI card in my WinXP system. I just purchased an iPhone and docked it near these monitors. Whenever my iPhone uses its internal radio for cell traffic (e.g. receiving calls or text messages), my primary 2000FP goes dark. The secondary monitor, (which is actually a bit closer to the iPhone) appears unaffected. Usually the monitor will come back after about 4-8 seconds, but sometimes it will remain dark until I use the input selector button on the monitor to cycle through once and return to DVI-D.

This may be irrelevant, but the iPhone is connected to the USB port of the primary monitor.

This is obviously quite annoying, and I'm wondering if there is anything in the way of drivers or configuration that will prevent this from happening. Or is this a defective monitor?

Thanks for any input.
Dedicated MacNNer
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Dec 3, 2007, 03:08 PM
Have you tested this by not having the iPhone plugged into your monitor (or computer) in any ways, just use the wall charger and see if it any interference happens.
I have my iPhone underneath two monitors (at work) all day and receive calls, messages, emails, etc. and neither monitor ever has had a problem. The only thing that seems to be affect is a co-worker's speakers whenever my phone is accessing the cell network, but this happens with many phones in todays market, plus he seems to find it fun to tell me every time my phone is connecting to the cell network.

If your phone is not connected to your monitor and you still have the problem I would try to move the phone further away slowly and see what happens.

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Dec 3, 2007, 03:25 PM
Ive never heard of GSM interference affecting LCD monitors. They're typically shielded well enough to reject most EMI.

If possible, see if any other GSM phones (from ATT and T-Mobile in the US) have the same effect on the monitor. However, given that one monitor is totally unaffected, I suspect that either that monitor or its cable is defective.

For your sake, I hope it's just the cable!
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Posting Junkie
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Dec 3, 2007, 03:37 PM
Originally Posted by Snice View Post
This may be irrelevant, but the iPhone is connected to the USB port of the primary monitor.
Ten to one this is not irrelevant at all, and that Dell's USB hub circuitry is cheap and/or ****ed up.

Plug the phone directly into the computer or into a wall outlet.
Mac Elite
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Dec 3, 2007, 08:53 PM
I've seen more interference with my iPhone than any other GSM phone I've ever used... And as a recovering phone whore (cured since last June), I've used many.

One of my clock radios is admittedly cheap, but no other phone interfered with it. I can't keep my iPhone on the same nightstand as that radio.

Even more serious, I'm a police dispatcher/911 operator. My iPhone has to be at least 2 feet from our Motorola Centracom Elite dispatch console. Everone I work with keeps their cellphone on their desk in front of 'em. Not me. Mine's gotta be on the other side of my workstation.

Neither is a dealbreaker, but interference is definitely there with the iPhone.
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Cold Warrior
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Dec 3, 2007, 09:04 PM
I've used a motorola GSM phone next to alarm clocks before, and it routinely causes noise in the radio's speakers.
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