For the connection script to work properly, your Raspbian installation needs a few prerequisite packages. The most important of these is the PPP daemon “pppd” and IP Tables to route packages.
sudo apt-get update sudo apt-get install ppp iptables
In the next chapter we will download and install vmodem onto your Raspberry linux box!
sudo mkdir /boot/vmodem sudo wget http://www.steptail.com/_export/code/guides:virtual_modem:script?codeblock=0 -O /boot/vmodem/vmodem.sh sudo wget http://www.steptail.com/_export/code/guides:virtual_modem:script?codeblock=1 -O /boot/vmodem/1.sh sudo wget http://www.steptail.com/_export/code/guides:virtual_modem:script?codeblock=2 -O /boot/vmodem/ppp.sh
The VModem script has been preconfigured to use ttyUSB0 as the default serial port name. Usually Raspbian will call its first serial port adapter ttyUSB0 when using USB to Serial converters, and you will not need to modify this script. However, if the name is something different, such as ttyAMA0, you may need to update the script to point to the correct serial port name. The following section described how to double-check your serial port name:
To confirm your serial port name, do the following:
/dev/ttyUSB0listed, you will need to update the script with the correct serial port. Visit this page to update the script with the correct serial port.
/dev/ttyUSB0listed, continue on!
This would be a good time to test your network to eliminate any future headaches.
Over SSH run the command:
To test VModem, you should be able to simply run the script. Test it first over SSH to see it's output:
cd /boot/vmodem sudo ./vmodem.sh
Check out specific guides on how to interface different computers and devices with VModem:
Make sure vmodem.sh is running on the Raspberry Pi first before attempting connection!
After you have verified that the VModem works properly on the console (see previous section), and you are able to connect to the Internet, you can make VModem run automatically as a background process after the Raspberry Pi is powered on.
There are two ways you can do this:
1) You can either run the following command which will automatically add VModem to your /etc/rc.local:
sudo sh -c 'printf "`head -n -1 /etc/rc.local`\n\ncd /boot/vmodem\n./vmodem.sh &\n\nexit 0\n" >/etc/rc.local'
2) Or you can edit your rc.local manually. Make sure your /etc/rc.local has the following at the bottom:
# Start serial port and simulate a modem cd /boot/vmodem/ /boot/vmodem/vmodem.sh & exit 0
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