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A couple years ago during a Black Friday sale I purchased one Toshiba WT7-C Windows tablet. Featuring an Atom Z3735G processor and 1Gb DDR3 RAM, it's basically a full featured PC in a 7" tablet form. It had one MiniUSB port for charging and that's about it. No 3G, no GPS. I did say it was cheap, didn't I?

One year passed and I barely used it, mainly because the battery wouldn’t last more than a 3-4 hours on intense use. Then came the Windows 10 upgrade and I had just enough space for it. Barely. Windows 10 made it more responsive and I could finally use the native 1280x600 resolution. (owners surely know what I mean)

It was still borderline unusable because the small battery wouldn’t survive a full day. So I started using it in a self-made cradle, as a TuneIn music player, connected to the charger. I knew It had OTG support, I tried it with one OTG flash drive and it worked immediately. But it was either OTG or charging, not both. Searching for that matter online, I found some USB Y split cables claiming to support both data and charging at the same time but I knew I can make myself one. Or at least I can try.

Step 1: The Illusive "charging Downstream Port"

My first try involved splicing one OTG cable and injecting power from a third connector (simple Y with OTG). When I first connected my cable, I had data connection (the flash drive became visible in Windows Explorer) and the power indicator said charging but I quickly noticed the power level going down. So no joy. BatMon software made it obvious, there was still a charging status but nothing actually happened.

A few weeks later, while searching the matter online I came across this:

Two types of charging port exist: the charging downstream port (CDP), supporting data transfers as well, and the dedicated charging port (DCP), without data support. A portable device can recognize the type of USB port; on a dedicated charging port, the D+ and D− pins are shorted with a resistance not exceeding 200 ohms, while charging downstream ports provide additional detection logic so their presence can be determined by attached devices. (Wikipedia)

It became clear to me that I would need some kind of detection logic and that there's no DIY solution for this. That's what every forum I came across said. But I only became even more stubborn. I found some dismantling instructions on FixIt and I was determined go all the way and seep into the battery connector with some external li-ion charger, bypassing the onboard solution completely while ripping the whole thing open. Then I saw I still have about two years of warranty and common sense kicked in.

Up to that point I purchased one HAMA OTG USB hub. I figured I will need it . It had a micro-usb power connector on a side, for supplying additional power to the devices connected to its ports, two regular USB ports and one OTG cable to connect to the tablet. Opening it, I saw one SMD diode preventing power to flow from that port back to the tablet. I shorted it and tried it on that tablet. OTG data connection worked but still no charging. I figured the OTG input cable is to blame so I unsoldered it and replaced it with a standard micro USB. This move provided me with data transfer but fake charging. Then I started playing with resistors across the data lines. I figured the worst case scenario would have been to end data connection for that session and starting a high current charge process until reinsertion.

Step 2: It Works!

Then I found it: one 200 ohms resistor across the data lines. That tricked the tablet into charging at high current while still maintaining the data connection. I don’t fully understand why, but it does work. I now have on my desk a tablet that's charging while connected to a wireless mouse and keyboard and a USB hard drive. BatMon is showing more that 1000 mAh charging rate, depending on the battery's status. I finally achieved my goal! It's the lowest power all-in-one PC ever!

The home edition of windows 10 doesn’t allow inbound RDP sessions but Teamviewer makes up for that. I'd like to use it for something more exciting that a seldom used internet radio player.

Now I'm opened to suggestions: What would anyone do with a 24/7 connected Windows 10 tablet that's able to connect via USB to any USB device? What are your suggestions? Please, let me know. :-)

<p>I really wish you could provide us with more detail on how you connected the resistor to the data lines. I am using an Insignia Windows 8 tablet as a PC substitute back home. I just write and edit text and some image files. It's connected to a TV so battery life gets extended to some four hours, but I would really like to be able to use it for a longer time. There is a cable for sale at Compact in the U.S., but I have some reservations about ordering and then having it delivered just to find that it doesn't work with my tablet or something like that.<br>Any input will be great.</p>
Hi there. I'm assuming you have basic soldering skills. If so, in order to replicate my setup, first, go pick a OTG USB hub and a regular mini-usb to regulat USB cable. Go home and open the hub up. You'll notice the cable that goest into the hub has four wires soldered on the board. Take it off. Now cut the regular cable in half and solder the mini-usb part to the hub's board. Make sure you replicate the exact same wire placement. The data lines are the white and green wires. Between those two wires solder your 200 resistor. The red (+5V) and black (Gnd) wires are connected to the original tablet charger. That's it. Hope it helps.
<p>whatever you would use a tablet for in the first place?</p><p>second room media center, kitchen pc, mail station, game computer for kids?</p><p>My 10&quot; android tablet gets used like a normal tablet, and &quot;docked&quot; to a dell desktop bluetooth kb/mouse for use as a second productivity computer, while my big box is busy reencoding video, or transferring large files... oh, Oh, OH, <strong><em>TOTALLY TORRENT TABLET</em></strong>!</p>
<p>oh, and/or splashtop. stick your big headless computer in the quiet time closet, and just remote in to it with splashtop</p>

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Bio: I am a graphic designer with many hobbies. I love electronics, computers, LEDs and all things tech.
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