[Lula] Question concerning ethernet wiring

[rcdawson at att.net]

My friend's RCA cable modem has both USB or ethernet connection points.  I have a question about its ethernet connection.  The instruction manual says that in order to connect a single computer to the modem you must use a straight through cable, but if you are to connect multiple computers using a hub or a "hub within a port switch that provides the same function," then you must connect the hub (or hub within a port switch) to the modem with a crossover cable  

Of course I didn't read the instructions before trying to set this up for my friend, so I  spent many frustrating hours with the modem and my computer both connected to a router with straight through cables. I won't try this again until next weekend, but I assume it will work if, as the instructions advise, I use a crossover cable between the modem and the router.

My question:  is this a standard way of doing things?  My home installation has a DSL modem, a router, and several computers all connected together with straight through cables.  I have never tried to connect two computers together directly, but I understand that if one does, one must use a crossover cable.

Who is following the standard, my DSL modem manufacturer or RCA?  Or is it left to the discretion of the manufacturer?  How does one refer to the "polarity" of a connection point?

I realize this question may be a bit off-topic, but where else could I find such a knowledgeable bunch of folks?