Do try http://www.3com.com to obtain the manuals. Since I don't own such a device, I would go there.
In closing you write " I also want to know how to use the 1000's MDIX downlink port to be connected to a cable modem." to which I respond that as far as I know, this is an INVALID AND DANGEROUS CONFIGURATION. The 1000 is not a NAT CAPABLE ROUTER and you will be exposing all the machines on the network directly to the internet.
DO NOT DO THIS. Go get some Linksys NAT capable router and use this inbetween the cable modem and your network.
Bob
I have two 3Com Linkswitch ethernet switches (models 3000 and 1000) and am needing to learn how to configure the VLan capabilities of them. I simply want to use them as ethernet hubs really. I also want to know how to use the 1000's MDIX downlink port to be connected to a cable modem. I have the users manual for the 1000, but not for the 3000. I appreciate any and all help. Thanks

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