How to check baud rate of NI-485 card !!!!

[Nok]

Hello...
I have to use NI-485 with the application at the baud rate 460,800 bps. I prefer to check the baud rate first.

I've already try to check by using digital oscilloscope to capture some data bit from the port but the signal is very low and I got just noise.

What could be the solution for this problem..

Thanks for any kind help.

[Chris_Rake]

The output voltage should be 0-5V. A good way to measure is to write a series of 0x55 ('U') at 8N1. This will generate a square wave with a frequency 1/2 the baud rate.