Which PXI switching modules won't degrade RS-422 communications?

[thisisnotadream]

I am developing a PXI-based application where multiple RS-422 busses exist whose signals can be monitored or traffic injected onto them.  As such, the lines need to be switched between RS-422 modules and actual units under test.  I don't want to introduce so much capacitance that traffic is degraded and engineering will blame their system issues on our test equipment.  Is there a special family of cards that should be used, assuming that the baud rate doesn't go above 115.2 kbaud?

Dan

[K C]

Hi,

If you choose a switch with a bandwidth say double of your baudrate it should not be a problem. Beside that in a testsystem you work with short cables so there is not much load to see for the driver.

I have a RS-485 application. To reproduce faults from the field I sometimes try to get the interface to fail wil resistive and capacitive loads. Try it you will be amazed how long it will work. 

If the design fails because of the load introduced by the switch then I don't think it is gonna work in the real world with bad cables and/or connected devices.