Connect tablet to wireless modem by USB cable

April 14, 2016 at 13:18:50
Specs: Linux
I have a tablet computer running Android 4.4.2, and a
Sprint MiFi 500 LTE wireless modem/router which I use
to connect to the Internet via the Sprint LTE cellular phone
system. I do not have phone capability, though.

The Sprint modem/router picks up the Sprint LTE cellular
signal containing Internet data and converts it to a WiFi
signal which is transmitted to the tablet.

Each device is battery powered, and charged by plugging
a USB cable with a micro USB connector into the device
and a male A-type USB connector into the charger.

Instead of plugging into a charger, the tablet can connect
to a computer by plugging the A-type connector into the
computer. This allows both data transfer and charging
the tablet from the computer.

The Sprint modem/router can connect to a computer in
exactly the same way. This allows a direct USB connection
between the computer and modem/router without using
WiFi, and also charges the modem/router battery.

Can I connect the tablet and modem/router by USB cable?

-- Jeff, in Minneapolis

See More: Connect tablet to wireless modem by USB cable

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April 14, 2016 at 14:53:58
It is rare to get clear description of what is what - how things are or can be connected at present. My compliments!

The only info I don't see is the actual make/model of your tablet computer. Whether or not that is critical here I'm not sure. If the tablet is a wifi only device (no Ethernet/cat-5 port) then I suspect you can't use usb to connect it to the router in order to connect to the web etc.. But not having tried it I could of course be wrong...

My memory is that with my iPad/iPhones I can connect to my assorted computers (Mac/Windows) via usb, and like you transfer data; but they cannot actually get online that way. My router is cat-5 (and of course wifi) only so to test out a usb connection to my router isn't possible.

Logically, if you have a usb cable that has the correct "ends" you could try it?

message edited by trvlr

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April 14, 2016 at 19:19:56
It may be that a USB cable with the correct connectors to connect
the tablet to the modem/router would blow up one or the other or
possibly both devices, so such cables are never made by anyone
who knows how to make them correctly. It would mean identical
male micro USB connecters at each end.

Back in the days of RS-232 ports, this could be done with an adapter
called a "null modem", which swapped some of the wires around so the
output from one end would go to the input at the other end, rather than
connecting input to input and output to output.

That might be what a USB On-The-Go cable does, but I have only seen
them used to connect a USB Flash memory stick to a tablet or phone.
It has a male micro USB connector to plug into the tablet or phone and
a female A-type USB connector to plug the memory stick into. I know
it isn't limited to memory sticks, but I don't know whether the idea can
extend to connecting a tablet to a modem. At a minimum, I expect that
it would require something analogous to a null modem adapter.

Connecting devices seems to require that one is the host and the other
is the client. The host provides the 5-volt USB power. When any device
connects to a desktop-type computer, the computer is the host. I doubt
whether either the tablet or the modem/router can act as a host.
I suspect they're designed to be clients only. I hope that's wrong.

-- Jeff, in Minneapolis

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April 15, 2016 at 03:30:07

shows the pinouts for usb

I think the power pins are set in stone; but with a usb "crossover" (as I will call it for simplicity) which is what used to be called a null modem cable, obviously the two data pins can be switched (at one end).

As Jeff comments there were (still are) also adapters (rs232) which did cross over for you to allow you to use standard cables between each device and the cross over adapter; and similarly for parallel port cables (db25). shows those pinout (out of interest...)

There are usb modules which allow you to check with a volt meter what's on which pin - at least the voltage pins... One of those would allow you to check on the modem/router what is what; if there is 5volts on the correct pins of the modem router - and on the tablet equivalent pins... then I would be inclined NOT to try connecting them directly...

There also usb plug in modules which display the volts for you; and also - on some - other info as well.

However after rereading your information and having gone through the above research/cogitations... I note that the modem/router is either charged by a charger or a computer. If the tablet is similarly designed... and doesn't produce 5volts usb power then you can't do what you suggest as with the modem/router and computer?

I would secure/get a usb voltage tester and see what each device puts out in terms of volts on the power pins. That way you will know if there are volts on the tablet; and also the modem/router.

Incidentally what is the power in/charger connector style for the modem/router; and similarly your tablet?

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April 15, 2016 at 12:07:33

> Incidentally what is the power in/charger connector style for the
> modem/router; and similarly your tablet?

I don't know that you're asking for anything more than what I said
in the third para of my original post: The tablet and the modem have
nearly identical chargers and virtually identical cables. Each charger
has a female A-type USB jack into which the male A end of the cable
is plugged. Each device has a female micro USB jack into which the
male micro end of the cable is plugged. Each device can operate
with or without its charger connected.

I bought the tablet second-hand from an organization which recycles
used computers. They gave me a charger which they believed to be
essentially equivalent to the original. It was made by LG and puts
out 5.1 volts at 0.7 ampere. The charger for the Sprint modem/router
is original and puts out 5 volts at 1.2 amperes.

I wonder if I could plug the tablet into the higher-amperage Sprint
charger without damaging the battery. I probably won't try it.

Oh! -- I just noticed that the Quick Start Guide for the tablet has a
section labeled 'Using Micro USB'. It refers to using a 'USB Cable'
OR a 'Transfer Cable', like they are different. One of the two may
refer to an 'On-The-Go' cable. It says in the same section that the
tablet can 'Connect to PC, another Tablet or Storage Device'.
I didn't remember that it said it could connect to another tablet.
That makes me hopeful that it might be able to connect to the
modem/router. The cabling ought to be identical. I also see now
that the tablet originally came with TWO cables -- one for charging
and one for data transfer. But the diagram shows both cables as
identical, with a USB male A-type connector at one end. That can
plug into a PC, but it can't connect to another tablet or a Flash
memory stick. Hmmmm....

-- Jeff, in Minneapolis

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April 15, 2016 at 13:16:27
Yes I think I was musing there re' the chargers: this link discusses the whole business of chargers...

To answer your query re' using a charger with a higher current capacity than the original. Provided all is well - the device being charged is OK - then no harm ought to occur using a higher amperage charger than the original.

For what it's worth, I have an original Apple charger for an iPad2 and another for an iPhone5s. I am charging both devices using this charger:

which has a higher current capacity and delivers higher current output - if required...; neither original charger delivers 2.4Amps...

re' usb connection between modem/router and the tablet...

Page 21 of the annual I download from Sprint - a pdf.

USB Tethering Driver for Windows XP

Click on USB Tethering Driver for Windows XP to download the driver for Windows XP.
This driver is only needed if you use a USB cable to connect the MiFi 500 to a Windows XP computer.

Would seem to suggest that a usb connection is a possible; albeit they are referring to an XP computer... But a tablet computer is computer... so in that respect the usb connection would appear viable; though to what end etc. and what may be possible...?

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April 15, 2016 at 15:46:46
Just to add to the higher amperage charger thing.

The amperage is it's "capacity" (ability). This is not related to what it "delivers" as this is a function of the load. So using a higher amperage charger will not damage anything at all.

Using a higher voltage one would be quite a different ball game as the voltage is applied to the device. Incorrect polarity can also damage things, unless they are protected against a reversal.

Always pop back and let us know the outcome - thanks

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April 16, 2016 at 15:05:51
It appears that there is just one electrical difference between
standard USB cables for transferring data and power between
a desktop-type computer and a portable device, and On-The-Go
USB cables for transferring data between portable devices:
Standard cables have pin #4 in the micro USB plug not connected
to anything, while On-The-Go cables have pin #4 shorted to pin #5.
The device at the end of the cable with pins 4 and 5 shorted together
becomes the host device. I think...

I'm going to plug the micro end of my On-The-Go cable into my tablet
and plug the regular cable from the modem/router into the other end
of the On-The-Go cable. If you don't hear from me again....

-- Jeff, in Minneapolis

message edited by Jeff Root

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April 16, 2016 at 15:37:01
If the all the stars in the sky start to go out then we'll know - erm...

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April 17, 2016 at 03:29:42
No joy. Except that nothing blew up. I tried the cables in both
possible orientations. With the On-The-Go cable plugged into
the tablet, the modem/router turned on when I turned on the
tablet. But the tablet settings continually reported "USB not

-- Jeff, in Minneapolis

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April 17, 2016 at 05:03:28
Not sure I know why the tablet reported as it did... But at least you found the answer - as in: no you can't achieve the desired end result. And the system didn't self-destruct
(nor the stars on the sky start to extinguish one by one - as per a certain scifi short story).

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April 17, 2016 at 12:03:32
Two possibilities I can't test without a cable I don't have: Connecting
the tablet and modem/router without shorting pins 4 and 5 together at
one end, and without (possibly) crossing the wires twice, since each of
the two cables connected in series may switch the wires from one end
to the other.

There must be nine billion possible combinations of cables.

-- Jeff, in Minneapolis

message edited by Jeff Root

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April 20, 2016 at 12:46:49
I'm thinking now that maybe connecting through a USB hub
could do the trick. Again, the objective is to connect the tablet
to the wireless modem/router via USB so as to eliminate the
need for the WiFi connection between them, the same as I know
can be done with a desktop computer. A hub might also allow
me to connect a keyboard and mouse at the same time as both
the tablet and modem/router are charging. Any thoughts?

-- Jeff, in Minneapolis

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