Version 15 started the 10 nodes and centralized voice-mail. The number of nodes is going to depend on which switch is used for the hub and it's growth capacity. I hope the DXP is not the hub, but a DXP plus or FX will be OK. At one time Comdial would not support anything less than a full clear channel T-1 but I know dealers that had it running on frame relay. With frame relay the voice-mail features suffered. Just remember that as you add nodes your chance of linking increases. That means be careful of reducing the number of channels.