Important: This documentation explains how to install ppp and establish an internet connection using the SimCom SIM800L. If you have not yet established a 2G connection through the modem, please refer to SimCom SIM800L: Setup (2G/EDGE Modem) first.
Install ppp before beginning the configuration.
apt-get install ppp
"internet.telekom" is my APN and must be changed to the providers APN
First we need to create a new file for ppp
sudo nano /etc/ppp/peers/rnet
Enter the following as the file's content. Make sure to change internet.telekom in line 2 to the APN of your mobile provider.
#imis/internet is the apn for idea connection connect "/usr/sbin/chat -v -f /etc/chatscripts/gprs -T internet.telekom" # For SIM800 use /dev/ttySC1 as the communication port # For SIM7600E use /dev/ttyUSB2 as the communication port /dev/ttySC1 # Baudrate 115200 # Assumes that your IP address is allocated dynamically by the ISP. noipdefault # Try to get the name server addresses from the ISP. usepeerdns # Use this connection as the default route to the internet. defaultroute # Makes PPPD "dial again" when the connection is lost. persist # Do not ask the remote to authenticate. noauth # No hardware flow control on the serial link with GSM Modem nocrtscts # No modem control lines with GSM Modem local
Save the file and exit. Now, edit the file
sudo nano /etc/chatscripts/gprs
Make sure the content of the file is the following:
# You can use this script unmodified to connect to cellular networks. # The APN is specified in the peers file as the argument of the -T command # line option of chat(8). # For details about the AT commands involved please consult the relevant # standard: 3GPP TS 27.007 - AT command set for User Equipment (UE). # (http://www.3gpp.org/ftp/Specs/html-info/27007.htm) ABORT BUSY ABORT VOICE ABORT "NO CARRIER" ABORT "NO DIALTONE" ABORT "NO DIAL TONE" ABORT "NO ANSWER" ABORT "DELAYED" ABORT "ERROR" # cease if the modem is not attached to the network yet ABORT "+CGATT: 0" "" AT TIMEOUT 12 OK ATH OK ATE1 # +CPIN provides the SIM card PIN #OK "AT+CPIN=1234" # +CFUN may allow to configure the handset to limit operations to # GPRS/EDGE/UMTS/etc to save power, but the arguments are not standard # except for 1 which means "full functionality". #OK AT+CFUN=1 OK AT+CGDCONT=1,"IP","\T","",0,0 OK ATD*99# TIMEOUT 22 CONNECT ""
ppp is now configured.
First dial by running
sudo pon rnet
Check in syslog, if the connection was successful. You should a report of your local and remote ip adress by pppd in the last few lines. You can also check ifconfig to see if the modem connection shows up as an interface.
tail -n 30 /var/log/syslog ifconfig
Now add the modem as a default route and try to ping a public IP (e.g. Google DNS)
sudo route add default dev ppp0 ping 18.104.22.168
If successful, the modem can be disconnected from the internet again
sudo poff rnet
First, open the interface configuration file
sudo nano /etc/network/interfaces
Make sure the file has the following content (usually three lines before source-directory have to be added)
# interfaces(5) file used by ifup(8) and ifdown(8) # Please note that this file is written to be used with dhcpcd # For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf' # Include files from /etc/network/interfaces.d: auto rnet iface rnet inet ppp provider rnet source-directory /etc/network/interfaces.d
Save and exit. Then open the rc.local file
sudo nano /etc/rc.local
Directly before the last line (containing exit 0), add the following
printf "Restart SIM800L\n" sudo echo "21" > /sys/class/gpio/export sudo echo "out" > /sys/class/gpio/gpio21/direction sudo echo "1" > /sys/class/gpio/gpio21/value sudo echo "0" > /sys/class/gpio/gpio21/value sudo echo "1" > /sys/class/gpio/gpio21/value
The modem should now automatically establish an internet connection whenever the pi boots.