If you know how to create the solution, then yes. But I found it easier to replace this with some android cell phone. We cheated big time and used a common Virgin Mobile phone at 35 bucks a month which here is cheaper than any USB broadband stick.
And it avoids you creating some box to convert the 232 to USB and a few months of board and code creation.
I'm not kidding you here. The office I'm in is doing a similar system on a grand scale and so the answer is yes but.
I have an Axis 2110 Network IP Camera which has been in use standalone with an external US Robotics V.92 modem sending an image every 15 minutes to my ISP/web site. Now I would like to run borth on solar 12 volt power. I'd rather not use an inverter which may not be efficient. Can I use a USB dongle external modem with the DB9 serial connection to the NetCam?