Notes: Multitech MultiModem GPRS and SLES10 SP1

Keywords: SuSE Linux Enterprise Server 10, udev, modem, GPRS, SMS

Overview:

The Multitech MultiModem is a USB GPRS modem that is capable of sending and receiving SMS text messages. It uses a Texas Instruments USB to serial convertor and while the default Linux kernel does have an appropriate driver module for this (namely ti_usb_3410_5052) - it is incapable of loading the necessary modem firmware. Fortunately, a suitable kernel module has been written and is available at http://www.brimson.com/downloads - however, due to changes in later kernels, the module wouldn't compile on SLES10 SP1.

I took the supplied patch for the 2.6.13 kernel, applied it to 2.6.13 and then looked at the differences between 2.6.13 and 2.6.16 (as shipped with SLES10 SP1). I then modified it so that these differences were incorporated while keeping the newer, required features. This was a quick, iterative process largely performed without consideration of the kernel internals.

Steps:

• Compile the kernel module using the updated source code from here; ( ti_usb_3410_5052.c & h)

• Read /usr/share/doc/packages/kernel-source/README.SUSE if you need help.
• Replace the old kernel module with the new one and run depmod.

• Copy the firmware to /lib/firmware (ensure it is world readable).

• Copy the following udev-rule file to /etc/udev/rules.d

  # File  /etc/udev/rules.d/99-multitech_multimodem.rules
  # ID 06e0:f111 Multi-Tech Systems, Inc.
  # Model: MTCBA-G-U-F1
  #
  SUBSYSTEM=="usb_device", ACTION=="add", \
  SYSFS{idVendor}=="06e0", SYSFS{idProduct}=="f111", \
  SYSFS{bNumConfigurations}=="2", \
  SYSFS{bConfigurationValue}=="1", \
  RUN+="/bin/sh -c 'echo 2 > /sys%p/device/bConfigurationValue'", \
  SYMLINK="modem"

• Plug-in the modem and dmesg should indicate a new device at /dev/ttyUSB* and create /dev/modem link
• If you have problems try loading the ti_usb_3410_5052 module with modprobe.

• The line should be set to 115200 bps with CTS/RTS flow control (at least this works for me).

October 2007