so im buying a D16y7/8 obd2B (white plug) dizzy

i have a 97 obd2A (blue plug) harness

i read a lot online but gave me mix answers
from my comprehension, OBD2B dizzy's dont have a blue wire (rpm tach??) to the plug while OBD2A DO have a blue wire connected to the plug.

my question is, when i wire up the obd2b dizzy (i got an extra obd2a plug to wire up the obd2b dizzy) into a obd2a plug, what do i do with the blue wire from the harness plug? can i get a extra wire and wire that to the dizzy (basically create a RPM tach signal wire into the dizzy) im assuming i got to wire the harness blue plug to something but dont know to what as the obd2b dizzy dont got the blue wire