Tach exchange

[HigginsTJ@aol.com]

Hello List,
 Ihave just bought an electronic tach and am unsure how to hooh it up.  I have 
a 73 spit currently with a cable driven tach.  My problem is I don't know what 
goes to what. On the back of the tach there are three connecting places, 1 is 
on the case (I guess this is the ground) and the other 2 are close together, 
one is a round male connector and the other is a male spade type. Can anyone 
help?
Thanks,
Ted