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  #1  
Old 18 August 2009, 06:53 PM
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Cell Phone Cell phones deactivate card keys

Comment: I have heard many times that a cell phone can deactivate a hotel
room magnetic key. Is there any truth to this?
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  #2  
Old 18 August 2009, 07:07 PM
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Brad from Georgia Brad from Georgia is offline
 
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It is if someone uses a cell phone to call the guy's wife and tell her he's in room 523 with a cute blonde.
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Old 18 August 2009, 07:09 PM
SoToasty SoToasty is offline
 
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Quote:
Originally Posted by Brad from Georgia View Post
It is if someone uses a cell phone to call the guy's wife and tell her he's in room 523 with a cute blonde.
Please, That does NOT deactivate a room key. I can deactivate the guy. Or possibly the cute blonde.
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  #4  
Old 18 August 2009, 08:37 PM
Mycroft Mycroft is offline
 
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In throry it could, but principly because of the permanent magnets in the speaker (and it would not have to be operating or even switched on).
In practise the speaker magnets are small and well shielded for the reason that cell phones tend to be kept in pockets/handbags close to bank cards etc; where any magnetic field would not be welcome,
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  #5  
Old 19 August 2009, 02:15 AM
blucanary blucanary is offline
 
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It's happened to me more than once. I didn't believe it would work before either. It's a pain in the butt too because it's easy to stick everything in the same pocket. Last year at the beach we had 3 key cards and everyone stuck them into their pockets with their cell phones. None of us could get into the room.
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Old 19 August 2009, 02:20 AM
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It's happened to me once too by storing the key in the same pocket as my phone.

Although correlation is not causation and all that...
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Old 19 August 2009, 02:24 AM
blucanary blucanary is offline
 
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Quote:
Originally Posted by Lachrymose View Post
It's happened to me once too by storing the key in the same pocket as my phone.

Although correlation is not causation and all that...
True but it's happened so many times to me now that I can't help but think there must be some link.
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  #8  
Old 19 August 2009, 03:03 AM
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I stayed in a hotel for 5 days this summer as a chaperone for dance convention, and kept having problem with the keys - so did the other moms - they told us that keeping them by cell phones would mess them up. We had about 7 cards between 3 girls and I and all of them had problems even after we tried to keep them away from the phones. *shrug* I finally got one card that worked reliably and kept it away from the phone (even though that was a pain in the butt when going down to the pool with just the phone, card, and a towel as it would have been handy to fold the card up in the phone) and it seemed to continue working.
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  #9  
Old 31 August 2009, 01:54 AM
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If it helps, my Blackberry Pearl has a built-in magnet near the back of the phone above the battery. The magnet has been known to pick up small paper clips, so it has noticeable strength. AFAIK, the main purpose is to react with another magnet in it's case or belt holster (also one that I've detected using small metallic objects) to place the phone in standby and lock the keyboard against accidental use.

Don't ask me why the magnet in the phone couldn't be replaced by a small metallic spring/relay that would open a suitable circuit when near the magnet in the case - I didn't design the thing!
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Old 31 August 2009, 02:23 AM
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My guess would be that since those cards are semi-disposable, that is the hotel does not care if you take them away after your stay, they are made to a much lower standard than say a credit card to keep costs down. That would include the materials in the magstrip. Any number of factors could come into play to stop it working. Friction between the card strip and other objects in your pocket might do it.

I have an embarassing TMI which I won't share, but it involved a gastric unfamiliarity with the local cuisine and a non-working cardkey which I wanted to access the bathroom in my room. A new cardkey was required - the existing one had simply died of old age and overuse.
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Old 02 September 2009, 07:47 AM
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Key cards are just really cheap, I think...though the last time I stayed in a motel, I always carried my card right next to my phone and it just kept letting me in. (It was a miserable room in a miserable motel, I kind of wish it hadn't...)

On a wildly unrelated note, my phone battery has a terrible time keeping a charge these days, but I notice it's always way worse whenever I spend more than half an hour at my friend's grandma and aunt's house an hour north of here, even if I charge it after leaving (and once I charged it overnight there, only to have the battery bars drip off the moment I unplugged it). I've noticed that my friend's aunt's phone is always beeping low battery there too. I haven't been over there in a couple of weeks now and my phone is acting much better. Is this just a coincidence going along with my phone being stupidly old by now, or is it something to do with their house? At first I thought maybe it was something to do with maintaining a signal on an hour-long highway drive, but it's definitely only when I visit them. What am I missing here that is the obvious, non-chemical explanation?
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Old 02 September 2009, 11:38 AM
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Quote:
Originally Posted by Native Medley View Post
Key cards are just really cheap, I think...though the last time I stayed in a motel, I always carried my card right next to my phone and it just kept letting me in. (It was a miserable room in a miserable motel, I kind of wish it hadn't...)

On a wildly unrelated note, my phone battery has a terrible time keeping a charge these days, but I notice it's always way worse whenever I spend more than half an hour at my friend's grandma and aunt's house an hour north of here, even if I charge it after leaving (and once I charged it overnight there, only to have the battery bars drip off the moment I unplugged it). I've noticed that my friend's aunt's phone is always beeping low battery there too. I haven't been over there in a couple of weeks now and my phone is acting much better. Is this just a coincidence going along with my phone being stupidly old by now, or is it something to do with their house? At first I thought maybe it was something to do with maintaining a signal on an hour-long highway drive, but it's definitely only when I visit them. What am I missing here that is the obvious, non-chemical explanation?
Some (possibly all newish) phones adjust their signal output to the local conditions. In a good reception area they put out less signal strength to reduce the load on the battery, in bad reception area the signal output is cranked up to max. This affects the drain on the battery. Even when you aren't making a call, the cellphone is intermittantly communicating with the network, so it can be ready if you want to make a call.

So it is possible that they either live at the edge of a cell, or there are obstacles between their house and the nearest cell tower that are causing the phone to work extra hard to find a signal.
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  #13  
Old 02 September 2009, 11:11 PM
HazyCosmicJive HazyCosmicJive is offline
 
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Hm. I keep my cell, my hotel keys, and my magnetic nametag all in the same pocket in my purse and I've never had a problem.

Anecdote disclaimer, etc.
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  #14  
Old 03 September 2009, 06:12 AM
Troberg Troberg is offline
 
 
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Quote:
Originally Posted by Eddylizard View Post
My guess would be that since those cards are semi-disposable, that is the hotel does not care if you take them away after your stay, they are made to a much lower standard than say a credit card to keep costs down. That would include the materials in the magstrip. Any number of factors could come into play to stop it working. Friction between the card strip and other objects in your pocket might do it.
I agree, they are usually crap quality. Here, they've even started skimping on the material, making them out of wood instead of plastic. Combine that with mechanical damage from a phone or a key ring, and they fail.

The speaker magnet is unlikely to erase it, as magnetic storage is very resilient to permanent magnets. I've tried to erase 3 1/2" disks with strong neodymium magnets, without success (I did it as a test of the safety of keeping the phone in the same pocket as the backup tapes). As far as I'm concerned, erasing disks with magnets is just a Hollywood myth.
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  #15  
Old 03 September 2009, 06:56 AM
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Quote:
Originally Posted by Eddylizard View Post
So it is possible that they either live at the edge of a cell, or there are obstacles between their house and the nearest cell tower that are causing the phone to work extra hard to find a signal.
Hadn't thought about the location...it makes sense, though they're only about a street over from my friend's house where I don't have that problem at all. The line must be really weird. I always get a consistently pretty average signal.

and my phone sucks anyway.
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  #16  
Old 03 September 2009, 07:26 AM
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Quote:
Originally Posted by Native Medley View Post
Hadn't thought about the location...it makes sense, though they're only about a street over from my friend's house where I don't have that problem at all. The line must be really weird. I always get a consistently pretty average signal.

and my phone sucks anyway.
Line of sight is the important thing. You can be 20 feet away from someone else and if there's a patch of old insulation or a microwave between you, you may well not get a very good signal where the other person's is fine. That's a big part of why no wireless company at least in this country can guarantee your phone will work *inside* of your house. The company I work for will even go so far as to send someone out to your area to make test calls in your vicinity to confirm things won't work (if they haven't gone out there before; the point is to find where our service really doesn't work, not to test whether people are lying or not).

What phone you're using can also make a difference. They really shouldn't - right now, every device that's out there uses pretty much the exact same radio - and yet I can point to a couple phones in our company's past lineup that do, legitimately, work in areas other phones do not. Both of the phones I can think of off-hand have these little flimsy antennas that you can extend from the device. Again, they *really* shouldn't work, but...
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