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 packets.
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
sudo chmod 770 /boot/vmodem/vmodem.sh sudo chmod 770 /boot/vmodem/1.sh sudo chmod 770 /boot/vmodem/ppp.sh
The VModem script has been preconfigured to use ttyUSB0 as the default serial port name. Typically Raspbian will call its first serial port adapter ttyUSB0 when using USB to Serial converters, and you won't 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!
For the sake of this tutorial we have used wired Ethernet. If you want to use Virtual Modem over a wireless connection, you will need to make sure it is properly set up, then update the script where it says
etherp=eth0 to say
etherp=wlan0 instead. To change the ethernet port in the vmodem.sh script, do the following:
sudo nano /boot/vmodem/vmodem.sh
etherp=eth0and change it to read
This would be a good time to test your network to eliminate any future headaches.
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
Go ahead and continue to the next part of this guide, where we will go through using Virtual Modem!