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TUCoPS :: Phreaking Cellular - Misc. :: cellshel.txt

Cell Shell - on getting internet access through a cellphone

[Cell Shell]======================================================[Morbie Angel]

This hasn't been fully tested (I've only tested the shell portion. It's
up to you to try out the PPP connection. In theory, it should work, but it's
going to be really slow.) And be forewarned, this is illegal. Everything you do
based on this is your choice, not mine. I am only supplying information, and I
am not responsible for your actions. If the FCC comes a knocking, don't be
bitching to me or LoU about your legal engagements. It is your fault if you get
caught doing any of the below in practice. Not mine.
The idea came to me a few months ago when I was in my friend's car, 
wishing that I could nab a few files off my system when we were on the road.
It completely dawned on me a few minutes later when I was playing with my 
Motorola 2800 bagphone. I had to find a way to make a network connection to my
main server back at my (old) house. And I figured cellular communication was
the way to go.
I went home later that day, and dug around my box full of (mostly)
various electronics and phone equipment. I found an old US Robotics 28.8 ext.
modem, RJ-11 -> Motorola TeleTAC adapter (For modems, duh.) and my old acoustic
coupler. I threw the external modem on my server, then ran some RJ11 to the 
adapter, and connected the adapter to the TeleTAC. Whee.
Now, client side, I popped the coupler onto the 2800, then connected it
to my amazing 14.4 on the lappy. Now how the fuck did I establish the god damn
connection? This is going to be a bit lengthy, so let's list it out.

1) I edited my inittab (/etc/inittab) and added a dialup term. (You can find 

2) Popped both cellphones into testmode. Nothing like FCN-00-**-83786633-STO.
Then I popped them onto an unused channel. And then (gasp) put them into Rx/Tx
mode by doing the following.
 a) 08#
 b) 10#
 c) 05#
 d) 353#

Oh my. I think we can hear ourselves talk over the channel. Isn't that special?

3) On the external modem, I threw a switch on it that said 'Auto Answer'. Now,
I realize this isn't on all Externals, and I should recommend that you find  
one, wheter it's at a Goodwill, or a vintage computer store. 

4) Started minicom on the laptop. And typed in the magical string, ATD.

Boom. That's all it took. I got an amazing 19.2 connection over the cellular
link. Now, could you get a higher connection with faster modems? No, dumb ass.
You can probably get a 28.8 connection, but it will most likely time out.
Now, unless you have some really old towers around your area that 
actually forward channels through different towers (i.e. You're driving down
the road, and you're out of the original tower's range, then you switch over.)
you're going to get disconnected if you pass the limited range of your tower,
which is anywhere between 6 to 10 miles. There is only a couple ways around 
that, but I'm sure you can figure them out within a few hours, minutes, or 
seconds from now. 
Okay, so you have yourself a cellular shell. Whoop dee doo. Now if you
can actually make a networked connection over the link, that would be nice, eh?
Well, using the wonderful PPP protocol, we can!
Add a new user on your host, name it whatever the fuck you want. Now,
for the shell, make sure it's /u sr/sbin/pppd. Make a new file in your favorite
editor called .ppprc and put it in the user's $home. Put the following in it.


Whoop, there it is. Now on the client side, make a ppp script that logs in
as that user. And that's all she wrote. It should work, but I make no 
guarantees whatsoever, since I never tested it. 
So play around with it, if you dare. Mail me some followups, additions,
and so on also, I'd like to hear some new ideas to add to this simple project.
Next time, I'll get in depth with more wireless networking projects for your
geeky enjoyment.

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