Gammu SMS messaging and GSM/3G modem

<todo>Document basic hardware check to make the 3G/USB-dongles work</todo>

[gammu]
port = /dev/gsmmodem
model =
connection = at
synchronizetime = yes
logfile = /var/log/gammu.log
logformat = errorsdate
use_locking = yes
gammuloc =

To check if gammu is detecting the modem and if it locked (requiring PIN code)

gammu identify
gammu getsecurity status

If is requiring you to enter PIN, use:

gammu entersecuritycode PIN -

For example:

# gammu identify
Device               : /dev/gsmmodem
Manufacturer         : Huawei
Model                : unknown (E3533)
Firmware             : 21.318.27.00.180
IMEI                 : xxxxxxxxxx

# gammu getsecuritystatus
Waiting for PIN.

# gammu entersecuritycode PIN -
Enter PIN code:

# gammu getsecuritystatus
Nothing to enter.

# echo "All your base are belong to us" | gammu sendsms TEXT 69393x927
If you want break, press Ctrl+C...
Sending SMS 1/1....waiting for network answer..OK, message reference=103

If it fails like:

# echo "All your base are belong to us" | gammu sendsms TEXT 666886825
If you want break, press Ctrl+C...
Sending SMS 1/1....waiting for network answer..error 500, message reference=-1
Unknown error.

Check if it is correcly registered in the network:

# gammu networkinfo
Network state        : home network
Network              : 214 03 (Orange, Spain), LAC 083E, CID 00CC4C7E
Name in phone        : "Orange"
Packet network state : registration to network denied
GPRS                 : detached

Seems the SIM is invalidated…