3-Com Switch 3C16479 Question

You might try using a swapped cable with those ports. They might be intended as uplink / downlink ports.

All ports on this switch are the same type . So it sounds like they are defective.

gwtx2 wrote in part:

If they're not X-over uplink (usually marked) as suggested by other posters, they're probably defective. It is not unusual to find fried ports on used equipment (if this is). Depending on lightening imponderables, I'd expect a port mortality of up to 1%/yr. Comments? Other's expererience?

-- Robert

Take a look at the diagram on page two of this document:

Hmmm, dubious.

More to the point is the paragraph on the right under the diagram:

All ports auto-sense an MDI/MDIX connection so each port can be connected to a device with a normal 'straight through' TP (twisted pair) cable or a 'cross-over' TP cable. Any port can therefore be used to connect to either another switch port, server, or workstation without additional configuration.

But the descriptive text below says "24 RJ-45 10/100/1000 Ports"

Did you buy the product yourself? If you did this comes with a lifetime warranty. Register it then raise an RMA. You should get a replacement switch.