Elesys 5450 Reference Manual page 57

Note
All memory boards used in upgrading the memory
configuration of the controller must adhere to the
JEDEC standards for 72-pin SIMMs. Single-sided
SIMMs placed in slot 2 must have at least one of the
Presence Detect jumpers in place: PD1, PD2, PD3,
or PD4.
For more information, locate JEDEC Standard No.
21-C, pp. 4.4.2-1 through 4.4.2-16. A copy of these
pages may be obtained by searching the following
web site:
http://www.jedec.org.
45