A customer has been sold an AVAYA IP OFFICE system for some new premises still under construction. I'm trying to understand how it works, but the BT salesman concerned knows nothing useful. There are several IP phones and something called "IPO (R8.1) 4 x 6 VOIP + LAN (BRI) Essential". I take it this is the device (PBX) that routes calls from one phone to another, and to/from the outside world which will be connected using ISDN2e. Presumably the IP phones connect via Ethernet cable to PBX - yes? Where do the IP phones get their IP addresses from? For example, does the PBX contain a DHCP server? If not, and I provide a separate DHCP server (perhaps in an internet router), can other devices share the same LAN subnet, or do I have to separate them either physically or by configuring a VLAN? Does the PBX integrate with the computers? For example is there a client I can run on a PC or Mac which will look up the details of an incoming call and pop them up on the screen? TIA