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ModemManager, now with Iridium satellite network support

ModemManager and the Iridium satellite network

I recently sent a new ‘iridium’ plugin for review upstream, this time for Iridium modems. The plugin was developed using a Iridium 9522B Satellite Transceiver modem connected through RS232, properly handled by ModemManager’s plugin system thanks to the extended RS232 support available in git master. The ‘iridium’ plugin handles these modems as any other GSM modem, even if it has nothing to do with GSM technologies.

Iridium is a constellation of 66 active (plus spares) LEO satellites orbiting at an altitude of 781 km, which gives phone and network coverage to every point in Earth. It was initially thought to be a constellation of 77 satellites, therefore named ‘Iridium’ after the chemical element with atomic number 77. The name didn’t change to ‘Dysprosium‘ when it was redesigned to maintain only 66 active satellites, no wonder why.

Even if the Iridium modems expose a GSM-modem like AT command set, several special things needed to be considered. For example, IP address setup via PPP needed more than the 20s hardcoded in NetworkManager, due to the extreme latency of the satellite network. Therefore, NM was also updated to allow ModemManager plugins to specify a specific ‘IpTimeout’ value.

See my email to the NM mailing list for further information on how to use ModemManager with Iridium support.

Ammonit Measurement GmbH sponsoring some hardware for ModemManager development

In Lanedo we have worked with Ammonit Measurement GmbH to help them with the improvement of ModemManager to handle Wavecom, Cinterion and Iridium modems. The guys at Ammonit were kind enough to sponsor some modems, so that I can spend my free time in developing and improving ModemManager, as well as in testing the modems before stable releases (Dan will probably be happy for that):

  • Sierra Wireless Fastrack Xtend FXT009 (GPRS modem, USB, handled by the ‘wavecom’ plugin)
  • Cinterion TC63i (GPRS modem, RS232, handled by the ‘cinterion’ plugin)

So, thanks Ammonit!

Fedora 10 in Asus Mini Nova Lite PX24 (2): Wireless Networking

My friend Tomasz gave me yesterday the configuration to enable Wireless Networking at system-level (skipping NetworkManager) for Ubuntu. It’s just modifying /etc/network/interfaces to setup the Wireless device directly there:

auto lo
iface lo inet loopback
 
iface wlan0 inet dhcp
wireless-key s:your_f****_password_here
wireless-essid your_f****_essid_here

I wanted the same in my home Fedora 10 server, but as you already may know, Fedora 10 is based on Red Hat, so forget about the debian-like network configuration, and welcome to the system-config-* scripts!

You can edit your system-level network configuration, executing, as root:

$> system-config-network

(or clicking on System->Administration->Network)

In the Wireless Settings tab you should select “Managed” mode, and I also specified the correct SSID of my home wireless network. Be really careful if adding the WEP key in HEX, as you must prepend “0x” to the whole key or it won’t work.

I thought that this would be enough, but nope. NetworkManager is launched by default at system startup, not the /etc/init.d/network script, which is disabled by default. You just need to disable NetworkManager, and enable the standard “network” script in order to have the system-level wireless configuration, executing, as root:

$> service NetworkManager stop
$> chkconfig --level 35 NetworkManager off
$> service network start
$> chkconfig --level 35 network on

I really like chkconfig, but not sure if the “service” command is a needed replacement of executing the script from /etc/init.d directly.

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