D-Link DFE-2600 User Manual page 17

If there is a switching circuit in the hub (or in any hub in a stack), it will serve
as a bridge between the two repeaters.
Switching
Circuit
100Mbps
Ethernet
Station
The switching circuit does not, however join the 10Mbps Ethernet collision
domain with the 100Mbps Fast Ethernet collision domain; it only allows them
to communicate. The two repeaters are two separate collision domains re-
gardless of whether a switching circuit is present.
If a DFE-2600 series hub or hub stack is uplinked through a twisted-pair or
Uplink port to another dual-speed or Fast Ethernet hub or stack, the hub will
function as a Class II Fast Ethernet device and be subject to those connectiv-
ity rules. If it is uplinked to a 10BASE-T Ethernet hub or stack (10Mbps
only) then it will function as a normal 10BASE-T Ethernet repeater and is
then subject to those connection rules. And because it is a dual-speed hub
with two separate repeaters, it can connect to both at the same time, counting
as a repeater in each of the collision domains. For more detailed information,
please refer
Introduction
100Mbps 10Mbps 10Mbps
Ethernet Ethernet Ethernet
Station Station Station
to Chapter
10Mbps Repeater
100Mbps Repeater
NWay Detection
RJ-45 Ports
100Mbps
Ethernet
Station
4, Making Connections.
5