I have an sl1100 with 3 incoming lines. The problem is if I answer one incoming call and another comes in to the call group I cannot answer it from my station. I have to go to a different station to answer the call. It does not matter if the other call is placed on hold or finished and I hang up it still will not allow me to answer the other call. Currently the call route to a call group.

Do you have line appearance on all 3 lines?

No sure what you mean by line appearance.

Dans is referring to some basic programming on the system - I would recommend finding a local authorized NEC tech to help you out with this issue. You can put a request in on this site for a tech in your area.