Question: My DSes do not work when they are connected to 10BaseT hub. In this case their green link LED is on, but connection with EM202 is not possible (no ping, DS manager does not find them either by auto discovery of from address list). When I connect these DSes directly to 100BaseT switch (green link LED, and yellow 100BaseT LED are ON) then everything works fine.
Do you have any hint what may be the reason?
Answer: The DS works fine with all standard types of hub. However:
One thing that which is important to remember is that many hubs are “smart” hubs these days. Let me give you an example:
PC ←→ 100BaseT HUB ←→ EM202 (works)
PC ←→ 100BaseT HUB ←→ 10BaseT HUB ←→ EM202
For the second arrangement to work after you have tested the first one you need to power 100BaseT HUB OFF and back ON- this will erase its internal MAC
lookup table!
Those lookup tables can be inconvenient. For example, simply try connecting EM202 to a different port of 100BaseT HUB – it won't work either! You will
need to reset the hub to make it notice that EM202 has moved.
