Recently there has been alot of news about how free charging stations could be reading data from devices that are plugged into them. The obvious solution to this issue is to place an adaptor between the charging station and the device that is only wired to transmit power.

I would sugest that the ideal design of would be a USB micro female to Apple dock male connector. This could be small enough to be carried around in a wallet and as USB micro is the current device charging standard compatability would be good.

This would also have an impact for non Apple devices where a USB micro passthrough addaptor could be used.

Does anyone know of any such device on the market?

This article is the inspiration behind my question.

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    Actually, the safest (and fastest) way to charge your Apple device is to use the AC adapter. Wall outlets are far more readily available and the adapters come free with your device.
    – user10355
    Commented Sep 15, 2011 at 11:12
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    @cksum - You've missed the point, of course using your AC adaptor is safer. But do you always carry your AC adaptor around with you? Commented Sep 15, 2011 at 12:02
  • Nope. But what makes carrying around an Apple to USB mini adapter any better? In either case, you still need to carry something.
    – user10355
    Commented Sep 15, 2011 at 18:24
  • This comment stream may be a dead horse but I do carry a compact USB - Dock connector cable in my (otherwise quite minimal) wallet expressly for use with USB chargers—be they charge stations, auto USB ports or a friend's generic device charger. I only have an AC charger if I'm carrying my gig bag.
    – jaberg
    Commented Sep 24, 2013 at 11:28

6 Answers 6


I know of no device that is sold to act as a write block that also allow full 1A charging, but Apple's patent covering potential upcoming changes to the dock connector might help you if you wanted a DIY hardware solution for the older 30 pin USB connectors.

In the mean time, you have several ways to secure the data without needing a custom piece of hardware.

  1. Lock your iOS device with a passcode before connecting it. This ensures the data is encrypted.
  2. You could go a step further and be ready to power off the device as soon as it's connected - shortening the window for the OS to be available to the charging station. The devices will still charge and shouldn't wake up unless it detects a disconnect/reconnect of the USB cord.
  3. Be careful to not establish trust with unknown chargers and computers by tapping when prompted by iOS 7.

Furthermore, if you upgrade to iOS 7, anytime you connect to a computer which could potentially read your data, you are alerted to this fact rather than having the device share all data because it's not locked with a passcode.

This new "trust this computer" functionality prevents any access to your device's storage without a positive user step to allow that access.

The device won't talk data to the "charging station" until the passcode is entered on the touchscreen. (Or the astronomically unlikely but theoretically possible chance that the charging station provides the one and only unique to you secure certificate generated and stored on your primary iTunes computer.)

The charging station can't try entering passwords one by one - so it's not like you are at more risk by charging an hour versus 2 minutes.


I recommend powering down the device before you connect it to any unknown docking stations or power chargers. The data is not accessible when the power is off and it will also recharge faster.

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    I would power it down after connecting or have the device already in the process of shutting down since when you plug in a device that it off, it starts up again.
    – bmike
    Commented Sep 22, 2013 at 12:20
  • Right - an answer that requires no cable mods or anything unusual. Commented Sep 22, 2013 at 18:39

If you use something akin to a Zoom Energy Bar you should be able to connect the mini USB at the charging station to charge the energy bar, then connect your device to the USB port. It should maintain the charge on the energy bar battery and charge the device(s) on the other end.

Added benefit of having a portable battery with you to charge various and sundry devices.

I have one of those energy bars, but I have to admit that I've never tried what I am proposing here.

  • Good idea - It looks like that eaton charger also comes with a smaller battery and a hand crank! grainger.com/Grainger/…
    – bmike
    Commented Sep 19, 2013 at 22:09
  • I think I might try it tonight and see if it works. I'll post back and let you know.
    – Kirk
    Commented Sep 19, 2013 at 22:38
  • It has to work since a malicious charging station would only be able to read / program the charger, not the device.
    – bmike
    Commented Sep 24, 2013 at 2:19
  • I was mostly curious about whether or not that charging bricking out take input and output at the same time. It seems to have worked -- I successfully charged by iPad one night using the brick that was also connected to the wall. So I think that this solution would fit the bill, even if it is somewhat convoluted.
    – Kirk
    Commented Sep 24, 2013 at 12:34

You could take a spare cable and remove the data pin from the plug that connects to the iDevice, so only power is transmitted.

  • That would work (I've actualy got a power only USB to Dock connector cable that came with a car charger) but isn't really practical. The point of charging stations is that they are conveniant and are just there. I would be looking for an adaptor that can be carried everywhere on my person. Commented Sep 15, 2011 at 12:45
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    Alot of things are smaller, especially the described micro USB to dock connector adaptor, which would be aprox the size of the male plug part of the cable (25 mm x 15 mm). I don't know about you but I wouldn't be able to fit a full size dock cable in my wallet. Commented Sep 15, 2011 at 13:59
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    I see an eventual kickstarter campaign to make something like a forensic read block device of similar form factor to the Scoche charging adapter
    – bmike
    Commented Sep 15, 2011 at 15:41
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    It's taken longer than I expected for someone to propose making the USB dongle I expected. Enter the USB Condom
    – bmike
    Commented Sep 17, 2013 at 1:22
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    My best guess is that if no signaling happens between D- and D+ most USB implementations will provide only 100 mA of current - see the non-standard USB section on wikipedia
    – bmike
    Commented Sep 17, 2013 at 3:47

I think this device fits the requirements. It has a switch to go between "Charge only" and "Sync and charge".

  • Can anyone tell what charging rate is selected when this cable is used? My research shows that if you just short the data pins (or leave them open) - USB computers will send 100mA of current and who knows what wall adapters will send to charge over the cables.
    – bmike
    Commented Sep 24, 2013 at 13:57
  • I don't know, but it says USB2 so presumably up to 500 mA? I trust that company to do it properly since they sell multi-iPad charging stations, etc.
    – beroe
    Commented Sep 24, 2013 at 19:54

I just wanted to chime in with a completely alternative answer. The data locking cable is really neat, but if you're really concerned, don't use a charging station.

Get a battery case, Or a battery pack. Or both.

Naturally, be sure to be on top of recharging them when you're in a safe place.

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