National Instruments VXI-1394 - Manual (Page 51)

Appendix C Advanced Hardware Configuration Settings
VXI-1394 User Manual for Windows C-10 ni.com
Figures C-7 and C-8 show two configurations for driving the external CLK
SMB from the VXIbus CLK10 signal by changing switch S2 to its alternate
setting. Switch S5 must be in its default position for these configurations.
Signal termination is not an issue when driving the signal, so the position
of S1 does not matter. The difference between these two configurations is
whether to use inverted or noninverted polarity when driving the signal.
Figure C-7. Drive Inverted External CLK SMB
EXT
CLK10
TERMINATE
Y N
SMB
TRIG TERM
OUT IN
NON INV
S1
S2
S3
S4
S5
CLK10 SOURCE
SMB ONBRD