You did not mention if the ATA was in a layer2 or a Layer 3 envireonment . either way , when the device gets its download , it will be a part of the information in the download .
At layer 3 , the default network vlan ( vlan 1 ) is used prior to the ATA getting a download and once the download is completed , the ATA will switch over to the new vlan in the download info from the NCP .