Allied Telesis AT-S63 - Manual (Page 306)

Chapter 21: VLANs and Multiple VLAN Mode Commands
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Adding both tagged and untagged ports to a VLAN using Syntax 1 takes
two commands, one command for each port type. For example, if you
had a VLAN called Service and you wanted to add port 5 as a tagged port
and ports 7 and 8 as untagged ports, the commands would be:
add vlan=Service port=5 frame=tagged
add vlan=Service port=7-8 frame=untagged
Using Syntax 2, you can add both types of ports with just one command:
add vlan=Service untaggedports=7-8 taggedports=5