I am writing this quick post as I recently had a very difficult time getting the Sierra Wireless 250u 3G USB modem from Sprint working on my Raspberry Pi. I also had seen anyone else on the web or forums having success with this combination. It turns out my main issue was that I was not using a powered USB hub. The Raspberry Pi’s only output about 100mA out of their USB ports and the 3G modem requires much more than that.
After I started using a powered USB hub, the configuration was straight forward. I am using the Wheezy version of Raspbian as my OS. This Belkin 7 Port Hub works out of the box.
The first thing I needed to do was check to make sure my device was recognized.
You should get a print out similar to this,
The important line we are looking for is:
Bus 001 Device 010: ID 1199:0301 Sierra Wireless, Inc.
Now that we have verified that the device is being recognized by the rPi, we need to install our dialer, WvDial. WvDial is a Point-to-Point Protocol dialer, it will enable a modem and start pppd in order to connect to the Internet.
sudo apt-get install wvdial
Then, edit the configuration file:
sudo nano /etc/wvdial.conf
I replace the entire contents of my file with the following:
Modem = /dev/ttyUSB0
Baud = 460800
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ISDN = 0
Modem Type = USB Modem
Phone = #777
Username = ''
Password = ''
Carrier Check = no
Stupid Mode = 1
Now, test the connection:
A succesful connection looks like this:
--> WvDial: Internet dialer version 1.61
--> Cannot get information for serial port.
--> Initializing modem.
--> Sending: ATZ
--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
--> Modem initialized.
--> Sending: ATDT#777
--> Waiting for carrier.
--> Carrier detected. Starting PPP immediately.
--> Starting pppd at Thu Jul 11 18:46:50 2013
--> Pid of pppd: 3395
--> Using interface ppp0
--> local IP address xxx.xxx.xxx.xxx
--> remote IP address xx.x.xx.xxx
--> primary DNS address xx.x.xxx.x
--> secondary DNS address xx.xx.33.x
There is a manual from Sprint located here if you have any troubles connecting, or just comment on the blog and I’d be happy to help debug with you. Thanks for reading.