3Com SuperStack II 9300 Command Reference Manual page 313

In an FDDI trunk:
You cannot modify FDDI station mode port pairs when any of the
ports in the pair are in a trunk.
When you modify the station mode, any FDDI ports that are
associated with virtual LANs (VLANs) or a trunk are removed from
the VLAN or trunk.
Within a trunk, you cannot change certain port characteristics, such as
FDDI station mode. For example, in an FDDI trunk, you cannot change
a trunked DAS (dual attach station) port to an SAS (single attach
station) port or an SAS port to a DAS port.
If you change an FDDI port pair from SAS to DAS, you select the pair
using just the lower of the two port numbers, just as with a trunk
anchor port.
Options
Prompt Description
Trunk index Index number of the trunk
that you want to modify
bridge trunk modify
Possible Values
One or more trunks
? (for a list of selectable
trunk indexes)
313
[Default]
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