It's no wonder every wal-mart I visited in a 20 mile radius was sold out of the Mifi, a battery-powered wifi hotspot and 3g modem. At $150 it's not cheap at all, but the supposed ease of set-up and ability to share internet with up to 4 wifi devices makes the convenience worth the price. Since I couldn't find one I opted for the Novatell Wireless MC760 usb 3g modem. At $80 it's much more affordable, but much more annoying to get working.
Only windows and mac are supported by the mc760. Normally this just means finding some half-working Linux driver and getting no support, which is pretty standard in the Linux world. In this case it's much much worse: you have to use windows or mac drivers and software to perform some magical rituals in the firmware before it'll even connect to the service. So there's really no way to use it without at least setting it up in windows or mac.
I of course didn't want to go along with this, mostly because it would be annoying to pirate a copy of windows just to get some crappy modem working. I tried for a couple days to get something to budge without a real windows install. I even eventually installed a VM of windows xp to try to set it up the "normal way" in a VM inside linux, but that still didn't work. I did end up using a windows machine to activate it finally. I'm still not sure I couldn't do it all from Linux, though.
So this is what I found out about the device. You plug it in and it does this wonderful thing where it pretends to be a USB CDROM and auto-runs a windows driver installer. The only way to turn this off in Linux is to use usb_modeswitch to detect the USB device and perform some magic to switch it to a ttyUSB0 modem/serial device. As usual, Slackware did this for me automatically without me knowing it, so I actually didn't even have to set that up.
The next thing I found out was how to configure the device as a modem. After hours and hours of googling and testing I found the secret ppp configuration that allows the modem to be controlled in Linux:
connect '/usr/sbin/chat -f /etc/ppp/peers/chat-virgin-3'
ABORT '\nNO ANSWER\r'
ABORT '\nNO CARRIER\r'
ABORT '\nNO DIALTONE\r'
SAY "CALLING ..."
Internet * Internet *
All you really need to dial up the modem is "ATZ\nATDT*99\n" or similar. Some people use 777, but 99 works for me. The PAP username and password is "Internet". Now, using just these settings with a completely pristine modem you can actually connect to Sprint PCS' network. You get a 10.0.0.0/8 address and two Sprint PCS dns servers (184.108.40.206, 220.127.116.11) and one P-t-P gateway: 18.104.22.168 (though that may just be one of several gateways). The very trivial auditing I did showed DNS worked but ICMP, TCP and UDP were almost nonexistent. Their firewalls seem to be non-shitty, however, a DNS tunnel would probably still work.
What's REALLY fucked up is virgin won't give you the URL to sign up or activate your card. You need to install the software and click on it to take you to a public URL they could have told you before. (Thanks a lot for wasting a ton of my time, virgin mobile) So you go to this URL and sign up with the device - NOT using the device, mind you. You need the internet (and a computer with administrator rights) to do that. Oh, and their website sucks - I had to call tech support for them to tell me to clear my cache and restart my browser about 4 times in between parts of the sign-up process because their shitty webapp couldn't understand the concept of expiring or reloading a cookie or session id. If you can just try to set the whole thing up with their customer service at 1-888-322-1122.
You register your address and credit card with the device's ESN and get a login/pin code for their website. Then you log in and pick a plan and fill it up with money. The login and an additional code for activating the card (the MSID) are both new phone numbers local to your zip code. With the software installed on a computer and an account set up, you can begin to activate the device. You connect once and the software redirects you to a very simple, easily guessable URL based on the phone numbers above. This then tells you new numbers (which IIRC were the phone numbers above) to insert in fields in the connection software to complete the activation process. When you go to plug them in you notice the default values are zeros along with the last 4 of the ESN. I saw some links during my googling which makes me think some specific AT commands would allow you to register the device without using Windows or Mac. Somebody please sniff the usb connection and verify this for me.
Does this activation process require your PIN code? No. Does this require anything but two phone numbers related to an account with money in it? No. Would it be possible to spoof more than one device on their network with the same settings at the same time? Perhaps, but I bet they have a way to find dupes. (Keep in mind, this MC760 also contains a GPS receiver which i'm still trying to figure out how to tap into)
Anyway. After finally disconnecting and connecting again, the internets is go. Unplug from the crappy windoze/mac you've been forced to use to activate this thing, plug it into your linux box, wait a minute and then run `pppd call virgin'. You should be connected, given a public IP and the internet should just do it's thing. The funny thing? All the settings once you're connected are the same as when we connected before the activation. Only the IP address is changed. HMMMMM. I wonder if we could just spoof an IP address and use the internets without activating? Again, this thing has GPS built in so don't think you wouldn't be tracked down.
The speeds i'm getting vary from 6Kbps to 1.2Mbps down and 1Kbps to 30Kbps up. This is not completely out of the range of current 4G connections, as embarrassing as that is for 4G users. So far in about half a day the connection has cut out twice for several minutes at a time and the card is extremely hot. I would recommend the Mifi if you have the cash.
edit when the usb card gets hot, it gets HOT. this makes performance suffer. example: