The Jumper Blocks of JP1 through JB12 are divided into three groups, each group of Jumper Block pertain to a different I/O module:
Jumper Block JP1-JP4: for I/O module number 0
Jumper Block JP5-JP8: for I/O module number 1
Jumper Block JP9-JP12: for I/O module number 2
In case that no I/O module is installed on any of the Jumper Blocks, those Jumper Blocks should be fully populated in order for them to function as a Digital Input Only ports.