The only difference is, when you connect your PC to a hub (instead of linking it directly with another computer) you can hook up with more computers. the speed will ofcourse lower a bit, but you won't even notice it.
A crossover cable is used to connect a Hub or Switch to another Hub or Switch - or a PC to another PC.
Straight Cable is used to connect a device to a different type of devices Eg: PC to a Switch PC to a Hub Switch to a Router E.t.c. Cross Cable is used to connect a device to a similar type of devices Eg: PC to PC Switch to Switch E.t.c.
A router allows communication between two different networks. A hub just links devices in a network.
It looks like you have problems with ip addressing. Make sure that both printers have different ip addresses and both ip address are in the same subnetwork as your PC and the laptop.
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A hub or switch must be used to connect 3 PCs together. Two PCs can be connected using a single crossover cable.
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A hub is a layer 1 network device (hardware), and the 'web' is a software concept implemented by different protocols and multiple devices.
| modem | wireless router - - - wireless PC ... | | | +-------------------- wired PC ... | hub ------------------- wired PC \------------------------ wired PC ... Routers have extra ports for wired PC but if you need more you need to have a hub. A hub though uses a cross-over cable to the router all the rest uses a regular network cable. All PCs of the network must point to the router's IP address as the default gateway and the network connection is allowed in their respective firewalls if any.
Unfortunately there is no solution for such situation; the reason why you get this message is the different protocols of your MP3 player and your PC. I guess your MP3 player uses USB port to connect and communicate with PC, am I right? Try to install the latest drivers for your PC's USB ports and for your MP3 player. You can try to use high speed "USB hub" (with USB 2.0) to connect your MP3 player to your PC, you will have MP3 will be connected to USB Hub will be connected to tour PC.