Saturday, October 30, 2010

Dismantling an HUAWEI E1550 HSDPA USB Stick

I've reading, some day ago, of a cheap method to add an sms-board to our electronics project using picmicro, arduino or other microcontrollers.

The method is quite simple and very very cheap: use a cheap GSM/USB modem! In the following link is described how to do this using a GSM/USB modem SKU12057: 

Modems usable to do this hack must support AT Commands. Once we have the command list of the main chip, interface modem to a microcontroller via an UART connection is matter of minutes!

I've a HUAWEI E1550 HSDPA USB Stick, distributed in Italy by mobile phone operator 3. I've opened it to see what chip uses. I'll show you some pics:

The two screws to remove are covered by a little piece of white adhesive paper:

Internally the circuits are covered by a small aluminum covers:

Once cover are removed, the chips becomes visible:

In this side, between the sim-card socket and the metal protection, there are some test-pads. Looking at Google I think those pads are used for JTAG programming of the chip. The chips in this side are:
  • Qualcomm RTR6285 (RF Radio Frequency transceiver for GMS/UMTS/GPS)
  • PM6658 (Power Management IC)

On this side the chips are:
  • Hynix "Hycouelom" F3R-2S60E (A flash memory where software and drivers for the use of USB stick are stored. This stick, in fact, is recognized as USB combo device and appears like a removable unit)
  • Avago AFEM7780 (UMTS2100 4x7 Front-end Module (FEM))
  • Qualcomm MSM6246 
The Qualcomm MSM6246 is the main CPU: HSDPA Modem with integrated Assisted GPS, High speed USB support and some other features not used by this USB stick such as 3Mpix camera support and QVGA video playback.

This chip is used also in some mobile phones (like the Samsung S8000) and I've not find useful info's... Only one link talking about this chip and Jtag:

Warning: those downloads are only available for subscribed users!

Avago AFEM7780 (UMTS2100 4x7 Front-end Module (FEM)) 

If you have datasheets and infos for use this usb stick as a UART modem... you're the welcome!!


  1. In the last picture, lower right part, is that a hidden socket for External Antenna?

  2. Have the same interest. I've found something about this chip MSM6250:
    or this link: (enter numbers and click green button "Скачать").

    Quote from one file in archive:

    Peripherals and Interfaces:
    I2C controller

  3. i have datasheet for MSM6246, write me if need

    1. i want it.... mail me at

      also tell me that how will i interface modem with arduino duo controller.

    2. Me too please,

    3. Hi karim ..
      I'm from egypt ,and I want to know if you had work huawei modem correctly with arduino via usb shield
      I strongly need it in this day

    4. This comment has been removed by the author.

    5. This comment has been removed by the author.

    6. I have a USB stick modem with MSM6246 cpu.
      Sir, please send me it datasheet.

      Thank you...