GSM

Work in Progress

This page is meant to understand how GSM network works by experiencing it. This wiki uses an USB 3G modem. Yet another help.

Setup

• Use a Huawei 1750
• 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

• To enter a pin code (i.e 0000). If a pin authentication is required if 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 network

+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 infortmations

+CREG: 5, 460055, 8BF06F

4655 = 18005 = Location area number

8BF06F = 7516441 = 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 ?)

Probably CSQ = O and RSSI

• Are all networks around me legit ?

You may look at your GPS position, lookup for known networks at opencellid.org and compare.