National Instruments VXI-USB - Manual (Page 43)

Appendix C Advanced Hardware Configuration Settings
VXI-USB User Manual C-6 ni.com
Figure C-6. Drive Noninverted External CLK SMB
Trigger Input Termination
Located within the group of CLK10 switches is switch S3, which controls
whether to put a 50
Ω termination on the external trigger input SMB.
Figure C-7 shows the setting for a nonterminated trigger input SMB. Use
the default setting of Figure C-7B to terminate the trigger input SMB.
Figure C-7. SMB Trigger Input Termination
S3 S4 S5 S6
OUT
IN
S2
From
Onboard
Oscillator
From SMB
CLK10 In
S1
Inverted
Noninverted
A. Does Not Terminate
Trigger Input
B. Terminate Trigger
Input (Default)
S3 S4 S5 S6
S2 S1
ON
OFF
S3 S4 S5 S6
S2 S1
ON
OFF