HOLD ENABLE:
double blue switch at top of board:
TOP:    Output 2 - left=enable Hold right=ignore Hold
BOTTOM: Output 1 - left=enable Hold right=ignore Hold

INPUT ENABLE:
The merger will process data from ALL inputs anyhow,
but will wait for end_event only on those that have been enabled.
quadruple blue switch just below previous one:

top          : input A : left=wait for End_Event right=ignore
2nd from top : input B : left=wait for End_Event right=ignore
3rd from top : input C : left=wait for End_Event right=ignore
bottom       : input D : left=wait for End_Event right=ignore

VME ADDRESS:
black 5-way switch near P1: set to all 0FF (left) on VIPA crates

use only to select Gegraphical Address in 0-32 range.
The 5 switches are GA(4-3-2-1-0) from top to bottom, left=0, right=1:

 switch (top to bottom)    GA0 GA1 GA2 GA3 GA4
 value if left              0   0   0   0   0
 value if right             1   1   1   1   1