Error -1073807298 generated by VISA Write

[L2]

Hi,

I am trying to write AT command to a wireless modem on an IBM labtop using VISA Write and got an error code "-1073807298". The same vi works fine on another computer with an external modem. Both PC got VISA Run-time Engine Version 3.1 for Windows 2000/NT/XP installed and the code is written in LabVIEW Version6.1.

I don't understand why. Would anyone able to help? Many thanks.

[Dennis_Knutson]

Is the wireless modem internal to the pc and does it have a driver for it installed and running? If that's the case, then you will probably need to uninstall that driver so that VISA can gain access to it and not the modem driver. With the external modem, you probably just have a com1 or com2 resource. In Device Manager or MAX, you should be able to see what ports are available.

[L2]

Hi, Thanks for your suggestion. The modem is a Sony Ericsson GC75 wirless internal modem. It requires a modem driver to get it function properly. When I uninstall the driver, the modem will not work. Is there any other suggestion? Many thanks.

[Dennis_Knutson]

I'm afraid I don't have a lot more to suggest. I've never worked with this type of modem. Is there an application program running in the background that you might be able to stop. You might want to investigate TAPI. This is an API for telecom apps. This is something I investigated a while ago and never really needed to implement. You should have an ActiveX object called Telephony class installed on your pc (assuming windows). There are methods for calling, etc. that might work for you.

[Shawn B.]

L2,

First you should verify that you are trying to communicate with the correct virtual COM port. You can find what virtual COM port is assigned to your modem by going to the Control Panel and selecting Phone and Modem options. Next you should verify that the COM port is not in use. You can check this in the Measurement and Automation Explorer. If you see an yellow exclamation point over the COM port it is in use by another application. If it is not in use you should be able to send it the AT commands that were provided in manual that came with you device.

Shawn B.
National Instruments