Asking this question for a friend

Does the helix units have to be gen 2 N to be able to network together! He is looking at getting a helix 7 and a 9 or maybe a 9 and a 10 but what ever he goes with he wants to be able to network em.and he is convinced that to be networked they have to be gen 2 N ?.I was thinking as long as they were a 9 or bigger They could be networked even if they were gen 1 ?