Well from how i understand it the eye is the same device but is wired differently for difference applications. (correct me if im wrong)
The BV7 beosystem 3's connection is a headphone jack as it only uses IR no contrast stuff is needed. When used with the Beolink passive I had a din connection to the same IR i assume for use with the buttons and IR.
I am not sure about the beosystem 3 it might be a different IR, A dealer should be able to get you the correct cable and confirm if you have the right IR.
Beovision 7 MKIV (Blu Ray)
Beolab 9
Beolab 6000
Beo 4
Beocenter 9300
Apple TV
SKY HD
Optoma HD65 Projector
Lintronic TT455-RT-238
Beovision 3 MKII