As stated above VLAN is enabled and assigned in the PBX not in the phones.
what is the Dot1Q functionality that the data sheet speaks of
802.1Q
The IEEE's 802.1Q standard was developed to address the problem of how to break large networks into smaller parts so broadcast and multicast traffic wouldn't grab more bandwidth than necessary. The standard also helps provide a higher level of security between segments of internal networks.
The 802.1Q specification establishes a standard method for inserting virtual LAN (VLAN) membership information into Ethernet frames.
A VLAN is an administratively configured LAN or broadcast domain. Instead of going to the wiring closet to move a cable to a different LAN, network administrators can accomplish this task remotely by configuring a port on an 802.1Q-compliant switch to belong to a different VLAN. The ability to move endstations to different broadcast domains by setting membership profiles for each port on centrally managed switches is one of the main advantages of 802.1Q VLANs.
