Recommendations for a data-only GSM/UMTS device in USB stick ff

David Pottage david at
Sat Nov 19 22:51:33 CET 2011

On 15/11/11 01:24, Michael Sokolov wrote:
> Hello Om community,
> Given that the GTA04 contains an off-the-shelf UMTS module and, if my
> understanding is correct, truly off-the-shelf GSM/GPRS/UMTS modems in
> the consumer USB stick form factor have been used during the
> BeagleBoard prototyping phase for the GTA04, I've figured that someone
> here might have some experience with / knowledge of these USB sticks,
> hence me asking here...

> * I need this device to be capable of placing old-fashioned data calls,
>   not just Internet access.  By old-fashioned data calls I mean the
>   arrangement where one dials a number from the mobile device with
>   ATD<number> (no semicolon at the end, making it a data rather than
>   voice call), and the number being dialed is a POTS land line with a
>   plain old analog modem answering the call.  I want to be able to
>   connect to my personal data center from remote locations bypassing
>   the Internet.
I think you will find that it is imposible to make data calls to an
analoge modem. The reason is that GSM and it's sucessor standards are
inherently digital, and are derived from ISDN telephone standards, so
nothing in your phone or in the phone network will create tones that
will be understood by an analogue modem.

Having said that, there should be no problem making data calls to
another GSM device or a digital trancever on the end of an ISDN phone line.

Given your other requirements for off the shelf hardware, I think your
simplest solution would be to buy a mobile phone with a data port, and
learn how to use that port as a GSM modem. For example I used to work
for Nokia, and I know that with their phones, if you put them into "PC
Suite mode" they will respond to AT commands on their serial/usb ports
and let you do dial up internet to your ISP, or any other phone number.
You may find that your current phone does what you need.

David Pottage

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