GSM
Work in Progress
Yet another introduction to understand basically how GSM network works by experiencing them. This wiki uses an USB 3G modem.
Contents
Setup
- Here a Huawei 1750 is used, many other should works.
- Serial port connection. It should bring 3 things in /dev, like ttyUSB0, ttyUSB1 and ttyUSB2 in Linux. Use it 8n1 9600 bauds, DTR/RTS ON on startup
- Terminal software :
Linux : use picocom : picocom --echo /dev/ttyUSB2
OS X: i.e coolterm. Use tty.HUAWEIMobile-Pcui among the 3 serial ports tty.HUAWEIMobile-Diag, tty.HUAWEIMobile-Modem, tty.HUAWEIMobile-Pcui
AT commands
- Get sure it's working type :
ATI
Manufacturer: huawei
Model: E1750
Revision: 11.XXXXXXXX
IMEI: XXXXXXXXXXXXXXXXX
+GCAP: +CGSM,+DS,+ES
- To enter a pin code (i.e 0000). If a pin authentication is required do it, it's needed to use other commands like network interactions.
AT+CPIN=0000
- AT+COPS? display the connected network, name and some infos
+COPS: 0,0,"F SFR",2
- AT+COPS=? Displays all available networks
+COPS: (3,"F-Bouygues Telec","BYTEL","20820",2),(3,"Orange F","Orange","20801",2),(2,"F SFR","SFR","20810",2),(3,"","","20815",2),,(0,1,2,3,4),(0,1,2)
- AT+CREG displays other informations on the connected network.
AT+CREG=2 Asks for advanced informations
+CREG: 5, 55002A, 2ED3
552A = 21802 = Location area number
2ED3 = 11987 = network cell ID
Try also
AT+CREG?
+CREG: 2,5, 55002A,2ED3
2ED3 is the local network cell ID
- AT+CSQ Displays the radio quality
+CSQ: 10,99
FAQ
- You may ask what happend if your have no available network around you (or if you're jammed ?)
MODE Command will probably display no service 0 and no submode 0 : ^MODE:0,0
AT+COPS? may answer 0 : +COPS: 0
A service state change indication can also be displayed : ^SRVST:0
- And when I got a network back online ?
Pretty much the same, you'll have service change ^SRVST, a new mode and obviously a new operator recognized with COPS command
- Are all networks around me legit ?
You may look at your GPS position, lookup for known networks at opencellid.org and compare. You can contribute to this project by exploring your environment.
