Ericsson F3507g Mobile Broadband Module

Even though Ericsson claims that their F3507g MiniPCIe WWAN/GPS card (USB ID 0bdb:1900 and 0bdb:1902) is compartible with Linux, they do not provide any information how to make this card work. Here are some basics:

• the card will not work without an inserted SIM, even the GPS function. If you want to use just GPS, any SIM would work, even if it is not attached to any active account with any GSM provider.
• the card provides USB interface, and is served by cdc_acm kernel module (apparently, for a while the option USB-serial driver claimed USB ID 0bdb:1900, but this was wrong, and as of kernel 2.6.28.9 that commit was reversed. You may need to blacklist the option driver to make sure it doesn't happen).
• it registers three pseudo-TTY's, in my case /dev/ttyACM0, /dev/ttyACM1 and /dev/ttyACM2.
• the card is controlled by sending AT-commands to one of it's pseudo-TTY's
• it appears that all three TTY's have identical funcionality. So, for example, we can use /dev/ttyACM0 for broadband 3G, /dev/ttyACM1 for controlling the card via AT-commands, and /dev/ttyACM2 for GPS, or in any other order.

Turning the card on

Before the card can be used, you have to turn it on. It is done by sending

AT+CFUN=1

to /dev/ttyACM1. The responce should be

OK

You can do it with any terminal terminal program like minicom. But we are not done yet. If your SIM is protected by a PIN-code, we may have to unlock it. This is done by sending

AT+CPIN="YOUR-PIN"

to /dev/ttyACM1. If your SIM is not protected by a PIN-code, or it is configured not to require one on connecting to the network, the last command is not necessary. Anyway, your card cannot be used for communication until it responds with

+PACSP0

Don't try to do anything until you see it.

Turning the card off

To put the card into energy-saving mode (this is the default), you can send

AT+CFUN=4

to /dev/ttyACM1. To remove all power from the card, send

AT+CFUN=0

to /dev/ttyACM1. Be carefull with the last command. It turns the card completely off, and it will no longer accept any AT-commands before the hard reset. To physically reset the card flip the wireless switch off, and then on. You can do the same by sending "0" to /sys/devices/platform/thinkpad_acpi/wwan_enable (to turn off) and then "1" to /sys/devices/platform/thinkpad_acpi/wwan_enable (to turn on).

Using the card as a wireless modem

Once the card is turned on, there are two ways to connect to the net. The first one is just to use the card as any "normal" GPRS modem and start pppd daemon on one of the pseudo-TTY's /dev/ttyACM* . The other way is supposedly more efficient as it does not require running pppd, and the catch is that it requires patching the kernel. But since this driver has not yet been accepted to the kernel, and there are reports that it is not (yet) significantly more efficient, we will stick with the first approach.

The easiest way to do it is to use wvdial. For example, to connect to AT&T Wireless network, your /etc/wvdial.conf would have to be something like this

[Dialer 3G]
Modem = /dev/ttyACM0
Init1 = AT+CGDCONT=1,"IP","proxy"
Stupid mode = 1
phone= *99#
Username = *
Password = *

Note: if you are using a SIM from a different mobile provider, you may need to change the access point name (APN) "proxy" in Init1 string and Username/Password to something else. You can find the appropriate APN here.

Using the card as a GPS receiver

Once the card is turned on, we can use it to get GPS info via NMEA protocol. First, you have to configure the a few NMEA options. It is done by sending

AT*E2GPSCTL=X,Y,Z

to /dev/ttyACM1. Here

• X can be 0 (NMEA stream turned off) or 1 (NMEA stream turned on)
• Y can be an integer form 1 to 60, and sets the frequency of how often the card emits the NMEA sentences
• Z can be 0 (DGPS is turned off) or 1 (DGPS is turned on)

so, to configure the GPSr to update every 5 seconds, and turn DGPS on, you would send

AT*E2GPSCTL=1,5,1

to /dev/ttyACM1. Once the GPSr is configured, we can get the NMEA stream on /dev/ttyACM2 by sending

AT*E2GPSNPD

to /dev/ttyACM2. Once you do that, /dev/ttyACM2 will no longer accept any new AT-commands. But you still can change the the behavior of the NMEA stream by sending the appropriate

AT*E2GPSCTL=X,Y,Z

to /dev/ttyACM1. Now you can read the NMEA stream by saying

cat /dev/ttyACM2

or better yet, start gpsd interface on /dev/ttyACM2.

Scripting everything

First you need to install the ppp, wvdial, sysfsutils and gpsd packages with

apt-get install ppp wvdial sysfsutils gpsd

I use sysfsutils to completely power off the F3507g card on boot, in order to save power (this is worth doing because on my X301 running the 3G device increases the power consumption by more than 10%. I have not tested how much more power is used if the device is not online and configured in low power mode, but it reasonable to assume it is more than zero). I also power off the bluetooth, disable the white LED in the power button, and instruct the kernel to use the noop scheduler for the SSD. Edit /etc/sysfs.conf to look like this:

block/sda/queue/scheduler = noop
devices/platform/thinkpad_acpi/bluetooth_enable = 0
devices/platform/thinkpad_acpi/wwan_enable = 0
class/leds/tpacpi::power/brightness = 0

These will now be applied on boot, but when the laptop wakes from sleep the BIOS seems to undo some of these settings, so create a script named /etc/pm/sleep.d/10sysfsutils:

#!/bin/bash
case $1 in
    (hibernate|suspend)
        ;;
    (thaw|resume)
        /etc/init.d/sysfsutils start
        ;;
    *)  echo "somebody is calling me totally wrong."
        ;;
esac

Don't forget to chmod a+x /etc/pm/sleep.d/sysfsutils. This script will be called when the laptop wakes up and it will power-off the 3G WWAN device again.

Now we need to set up wvdial to work with the 3G WWAN device. Edit /etc/wvdial.conf to look like this:

[Dialer 3G]
Modem = /dev/ttyACM0
Init1 = AT+CGDCONT=1,"IP","proxy"
Stupid mode = 1
phone= *99#
Username = *
Password = *

Note: you may need to change the access point name (APN) "proxy" in Init1 string and Username/Password to something else. Find the appropriate APN here.

Edit /etc/ppp/peers/wvdial to look like this:

noauth
name wvdial
usepeerdns
noccp
novj
novjccomp

Create a file called /usr/local/bin/F3507g containing the following:

#!/bin/sh

CONTROL_DEVICE=/dev/ttyACM1
GPS_DEVICE=/dev/ttyACM2

powerup_F3507g () {
        echo -n "Powering up F3507g card.."
        echo 1 > /sys/devices/platform/thinkpad_acpi/wwan_enable
        while [ ! -c $CONTROL_DEVICE ]; do sleep 0.5; echo -n "."; done
        echo "done"
}

turnon_F3507g () {
        echo -n "Turning on F3507g card..."
        /usr/sbin/chat -v "" "AT+CFUN=1" "+PACSP0" "AT" "OK" > $CONTROL_DEVICE < $CONTROL_DEVICE
        echo "done"
}

turnoff_F3507g () {
        echo -n "Turning off F3507g card..."
        killall gpsd
        /usr/sbin/chat -v "" "AT+CFUN=4" "OK" > $CONTROL_DEVICE < $CONTROL_DEVICE
        echo "done"
}

powerdown_F3507g () {
        echo -n "Powering down F3507g card.."
        echo 0 > /sys/devices/platform/thinkpad_acpi/wwan_enable
        while [ -c $CONTROL_DEVICE ]; do sleep 0.5; echo -n "."; done
        echo "done"
}

turnon_GPS () {
        echo -n "Starting NMEA stream on $GPS_DEVICE..."
        /usr/sbin/chat -v "" "AT*E2GPSCTL=1,3,1\r" "OK" "AT*E2GPSNPD\r" "GPGGA" > $GPS_DEVICE < $GPS_DEVICE
        gpsd $GPS_DEVICE
        echo " done"
}

Make this script executable with chmod a+x /usr/local/bin/F3507g.

Append the following lines to your /etc/network/interfaces file

iface 3G inet wvdial
pre-up . /usr/local/bin/F3507g; powerup_F3507g; turnon_F3507g
post-down . /usr/local/bin/F3507g; turnoff_F3507g; powerdown_F3507g
provider 3G

iface gps inet manual
pre-up . /usr/local/bin/F3507g; powerup_F3507g; turnon_F3507g; turnon_GPS
post-down . /usr/local/bin/F3507g; turnoff_F3507g; powerdown_F3507g

Now 3G connection could be started in the same way as you start any other network interface, just by saying sudo ifup 3G. To shut it down, say sudo ifdown 3G. Similarly, GPS interface is started by sudo ifup gps and turned off by sudo ifdown gps. Once you get a fix, you can use your favourite GPS mapping application like tangogps. The "cold start" seems to take quite a bit however, and sometimes it cannot get a fix if indoors.

Other thoughts

While AT+CFUN=* and AT+CPIN=* are pretty standard commands for wireless modems and are well-documented (e.g. here and here), it appears that the commands AT*E2GPSCTL and AT*E2GPSNPD are unique to the Ericsson F3507g card. All credit for discovering them goes to "Nickolai Zeldovich" who left a comment in this thread. I imagine one could find them via a USB sniffer on a working Windows machine (or a Linux machine with Windows running in a virtual machine). Another way to get them is to try to look for "gps" string in the Windows drivers. What is interesting, F3507g supports a few other AT-commands with "GPS" substring (you can get all supported AT-commands by sending AT* to /dev/ttyACM1 after activating it with AT+CFUN=1). Anyway, there is a project aiming to document all AT-commands for the Ericsson F3507g card.

Related Links

• F3705g - AT commands reference
• Carrier internet Settings (Apn, Gateway, etc)

Bugs

• Ubuntu: works natively only on kernels <= 2.6.27-10-generic. > 2.6.27-10-generic kernels will not power on the device appropriately in my testing. See Ubuntu bug here.

Models

• X200
• X301
• T400