How to set transceiver mode to 2-wire TXRDY Auto from Visual Basic

[Steve Case]

I am using a PCMCIA-485 adapter to interface to some RS-485 sensors. The sensors are connected using a 2-wire interface. I have developed an application in Visual Basic to control the various sensors. However, the application is dependent on the PCMCIA-485 adapter's transceiver mode being configured into the "2-Wire TXRDY Auto" mode. Presently I require the user to configure the transceiver mode by opening up the advanced setting dialog within the device driver for the adapter and manually setting the transceiver mode. I would prefer to have my application take care of this directly. Unfortunately, I cannot find any references that document how to do this.

Can I use Measurement Studio Tools for
Visual Basic to control the transceiver mode of the PCMCIA-485 adapter?

[Randy Solomonson]

Hello-

There is a registry key in Windows that can change this mode:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Serial\Parameters\Serial1000X\TransceiverMode

Try experimenting with it by hand first. It may also be necessary to reboot after changing this value.

Randy Solomonson
Application Engineer
National Instruments