Zoom USB modem on Windows

bmt22033 · Post by **bmt22033** » 31 Jul 2012, 23:15

I've got an unlocked Zoom Tri-Band USB modem that's installed on Windows 7 x64. When I plug the modem into the USB port, I see a mass storage device on the USB bus (no drive letter, not visible in Explorer) and the driver then launches the Zoom software suite. After a few seconds, the software UI indicates that the modem is connected to the (AT&T) network and I can then send/receive text messages, etc. using the Zoom software. If I then launch an app like Tera Term to try and connect to the modem so I can issue AT commands, I see three new serial ports:

COM18: HSPADataCard USB Device Management
COM19
COM20

Tera Term won't connect to COM18 at this point presumably because the serial port is locked by the Zoom software. I am able to connect to COM19 and/or COM20 and issue AT commands (I've tested this with several ATi# commands on both ports). However, as soon as I close the Zoom software, the modem seems to disconnect from the network. The COM ports don't disappear and I can still issue AT commands but most of them just return an error when the Zoom software is not running. Is it safe to assume that the driver and/or Zoom software suite is connecting/disconnecting the modem to the network? If so, would the functionality provided by USB_ModeSwitch enable/connect the modem without the need for the Zoom software? I'm writing my own software that needs to be able to send AT commands to/from this modem and it's not feasible/acceptable in this scenario to have the Zoom software always running.

For what it's worth, the modem I'm using can be found at http://www.zoomtel.com/products/4598.html. Thanks very much for any advice you can give me!

Post by **Josh** » 01 Aug 2012, 12:20

I'm not sure it's the driver that starts up the software.

Usually, there is a resident autostart task that in turn watches the driver. If you disable that ("msconfig" or registry RUN key), the device should be able to start up without being tweaked.

bmt22033 · Post by **bmt22033** » 01 Aug 2012, 16:30

Hi Josh. You're absolutely right about the resident process (MCtlSuc.exe) that kicks off the Zoom software when the modem is inserted. I killed that process and things seem to be working as expected now. Thanks very much for your help!

dune · Post by **dune** » 02 Aug 2012, 07:01

Just keeping a Shift key pressed while you insert the modem might also work - if there was no program you had to install when using the modem for the first time.