I'm confused. Are you trying to use the 3300 on a trunk port or and access port? If you are using a trunk port and the native vlan isn't the phone vlan then you should fill out the dot1q fields in the 3300. If you are plugged into an access port you should leave the dot1q fields default, because the switch doesn't want to see tagged packets on that interface. If you do tag them you'll probably just violate the MTU settings on the network and have a lot of packets dropped. The VLAN_OFF command defaults the dot1q settings on the 3300 so that it can be plugged into an access port. This is how we generally set things up but it isn't necessarily right. If you don't like to create access ports the dot1q settings in the 3300 would make it easier from the network switch point of view. On the other hand, if you remove the 3300 from the network switch and try to plug back in you won't be able to talk to the 3300 without doing encapsulation on your computer.