If you don't have IP sets, H.323 or SIP you really don't need the sig server. Without the above items all you would use it for is element manager. If it were a new system I would recomend that you put it in as Nortel will give you a much better price on it than if you purchase it later when you decide to add IP to your system. I'd also recomend that on a new system a few, 10, IP licenses (ISM) are included. Someone is bound to decide that they want to try it. You will only have to buy the VGMC card then.