Hi Jo,
This really just indicates the VLAN trunking mode that the port is currently configured for:
1. If a port is configured in access mode for a specific VLAN, it is referred to as Desktop mode.
2. If a port belongs to the voice and data VLANs (1 and 100 by default), it is referred to as IP Phone + Desktop mode.
3. If a port belongs to two or more VLANs it is referred to as Switch/AP mode.
2 and 3 above allow you to define the native VLAN (PVID) for handling untagged traffic.
Hope this helps,