# PPP over GPRS or HSPA link
This article illustrates how to set-up a TCP/IP link using the PPP protocol over a GPRS or HSPA network
The contents are tested on a [Terra-M Board ](/terra) with the embedded GPRS modem
##Enabling the PPP Kernel support
Follow this article to set up a cross compilation environment on your PC
to compile the Linux Kernel image for your board:
* @article='compile_linux_3_13'
Run make menuconfig and set-up the follow configuration:
Device Drivers --->
[*] Network device support --->
<*> PPP (point-to-point protocol) support
[ ] PPP multilink support (EXPERIMENTAL)
[*] PPP filtering
<*> PPP support for async serial ports
< > PPP support for sync tty ports
< > PPP Deflate compression
< > PPP BSD-Compress compression
< > PPP MPPE compression (encryption) (EXPERIMENTAL)
< > PPP over Ethernet (EXPERIMENTAL)
< > PPP over ATM
Create the new Kernel image and copy it on the first partition
of your bootable microSD then reboot the board.
##Install and configure the ppp package
Install the ppp package by typing:
sudo apt update
sudo apt install ppp
Edit the **/etc/ppp/peers/provider** file and insert the number to call
changing this line:
connect "/usr/sbin/chat -v -f /etc/chatscripts/pap -T ********"
in that way:
connect "/usr/sbin/chat -v -f /etc/chatscripts/pap -T *99***1#"
Set the serial line where is wired GPRS modem changing /dev/modem
in:
* /dev/ttyS1 If you are using a Terra-M board
* /dev/ttyACM0 If you are using Huawei HSPA USB Stick K3806-Z
Set the speed of the serial line in:
# Speed of the serial line.
115200
Using:
* 115200
Edit the **/etc/chatscripts/pap** file as shown below:
# You can use this script unmodified to connect to sites which allow
# authentication via PAP, CHAP and similar protocols.
# This script can be shared among different pppd peer configurations.
# To use it, add something like this to your /etc/ppp/peers/ file:
#
# connect "/usr/sbin/chat -v -f /etc/chatscripts/pap -T PHONE-NUMBER"
# user YOUR-USERNAME-IN-PAP-SECRETS
# noauth
# Uncomment the following line to see the connect speed.
# It will be logged to stderr or to the file specified with the -r chat option.
#REPORT CONNECT
TIMEOUT 60
ABORT BUSY
ABORT VOICE
ABORT "ERROR"
ABORT "NO CARRIER"
ABORT "NO DIALTONE"
ABORT "NO DIAL TONE"
"" ATZ
#Insert this line if you are using a Huawei K3806 HSPA USB Stick
#OK ATQ0V1E1S0=0&C1&D2+FCLASS=0
OK AT+CGDCONT=1,"IP","web.omnitel.it","0.0.0.0",0,0
OK ATDT\T
CONNECT ""
Change **web.omnitel.it** with the APN address of your provider. For example in Italy the Telecom APN is
**ibox.tim.it**.
##Turn-on the modem
If you are using a [Terra Board](/terra) turn-on the GPRS modem
using these programs:
### modem_on.py
from time import sleep
from ablib import Pin
print "Modem ON"
quectel_power = Pin('W10','HIGH')
quectel_power_key = Pin('E10','LOW')
quectel_power_key.on()
sleep(1)
quectel_power_key.off()
### modem_off.py
from time import sleep
from ablib import Pin
print "Modem OFF"
quectel_power = Pin('W10','LOW')
quectel_power_key = Pin('E10','LOW')
##Link up the GPRS connection
Now you are ready to link-up the GPRS connection. To check what will
happen open a new SSH session and type:
tail -f /var/log/messages
If __/var/log/messages__ doesn't exist probably you have to install rsyslog by typing:
sudo apt update
sudo apt install rsyslog
On the original terminal session type:
pon
to link-up the ppp session.
You could see the following messages on the /var/log/messages terminal session:
Oct 5 12:37:33 localhost pppd[1289]: pppd 2.4.4 started by root, uid 0
Oct 5 12:37:34 localhost chat[1290]: timeout set to 60 seconds
Oct 5 12:37:34 localhost chat[1290]: abort on (BUSY)
Oct 5 12:37:34 localhost chat[1290]: abort on (VOICE)
Oct 5 12:37:34 localhost chat[1290]: abort on (ERROR)
Oct 5 12:37:34 localhost chat[1290]: abort on (NO CARRIER)
Oct 5 12:37:34 localhost chat[1290]: abort on (NO DIALTONE)
Oct 5 12:37:34 localhost chat[1290]: abort on (NO DIAL TONE)
Oct 5 12:37:34 localhost chat[1290]: send (ATZ^M)
Oct 5 12:37:34 localhost chat[1290]: expect (OK)
Oct 5 12:37:34 localhost chat[1290]: ATZ^M^M
Oct 5 12:37:34 localhost chat[1290]: OK
Oct 5 12:37:34 localhost chat[1290]: -- got it
Oct 5 12:37:34 localhost chat[1290]: send (AT+CGDCONT=1,"IP","web.omnitel.it","0.0.0.0",0,0^M)
Oct 5 12:37:35 localhost chat[1290]: expect (OK)
Oct 5 12:37:35 localhost chat[1290]: ^M
Oct 5 12:37:35 localhost chat[1290]: AT+CGDCONT=1,"IP","web.omnitel.it","0.0.0.0",0,0^M^M
Oct 5 12:37:35 localhost chat[1290]: OK
Oct 5 12:37:35 localhost chat[1290]: -- got it
Oct 5 12:37:35 localhost chat[1290]: send (ATD*99***1#^M)
Oct 5 12:37:35 localhost chat[1290]: expect (CONNECT)
Oct 5 12:37:35 localhost chat[1290]: ^M
Oct 5 12:37:35 localhost chat[1290]: ATD*99***1#^M^M
Oct 5 12:37:35 localhost chat[1290]: CONNECT
Oct 5 12:37:35 localhost chat[1290]: -- got it
Oct 5 12:37:35 localhost chat[1290]: send (^M)
Oct 5 12:37:35 localhost pppd[1289]: Serial connection established.
Oct 5 12:37:35 localhost pppd[1289]: Using interface ppp0
Oct 5 12:37:35 localhost pppd[1289]: Connect: ppp0 <--> /dev/ttyS1
Oct 5 12:37:36 localhost pppd[1289]: Remote message: Welcome!
Oct 5 12:37:36 localhost pppd[1289]: PAP authentication succeeded
Oct 5 12:37:40 localhost pppd[1289]: local IP address 109.112.53.134
Oct 5 12:37:40 localhost pppd[1289]: remote IP address 109.112.235.129
Oct 5 12:37:40 localhost pppd[1289]: primary DNS address 83.224.66.134
Oct 5 12:37:40 localhost pppd[1289]: secondary DNS address 83.224.65.134
Typing:
sudo ifconfig
You could see a new network interface called ppp0.
sudo ifconfig
eth0 Link encap:Ethernet HWaddr 00:04:25:78:9b:9a
inet addr:192.168.1.90 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::204:25ff:fe78:9b9a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2985 errors:0 dropped:0 overruns:0 frame:0
TX packets:269 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:204683 (199.8 KiB) TX bytes:28898 (28.2 KiB)
Interrupt:21 Base address:0x4000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:280 (280.0 B) TX bytes:280 (280.0 B)
ppp0 Link encap:Point-to-Point Protocol
inet addr:109.112.53.134 P-t-P:109.112.235.129 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:5 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:74 (74.0 B) TX bytes:92 (92.0 B)
To link down the connection type poff.
Oct 5 12:39:08 localhost pppd[1289]: Terminating on signal 15
Oct 5 12:39:08 localhost pppd[1289]: Connect time 1.5 minutes.
Oct 5 12:39:08 localhost pppd[1289]: Sent 0 bytes, received 0 bytes.
Oct 5 12:39:08 localhost pppd[1289]: Connection terminated.
Oct 5 12:39:10 localhost pppd[1289]: Exit.
##ppp commands
pon Bring link up. Executes pppd (you may specify the ISP name
on the command line), and will immediately return the
command prompt while still dialing.
plog Shows the last lines of the pppd log. Basically, does
tail ppp.log.
poff Bring link down. Terminates connection by killing pppd.
##Links
* [What a Chat script means](http://www.tldp.org/HOWTO/PPP-HOWTO/x1219.html)
* [PPTP Client](http://pptpclient.sourceforge.net/howto-diagnosis.phtml#tty_einval)
@include='bio_tanzilli'
##Buy
* [Terra board](https://www.store.acmesystems.it/product-page/COMBO-M2)