+ 1 Votes DHCP issue? gechurch March 18, 2013 at 3:59pm PST Just so I'm clear, you are trying to use the ethernet to give you standard network (TCP/IP) access to another device, correct? (As opposed to, say, carrying the serial cable over ethernet cabling). And what is the error when trying to connect? Does it say the cable is unplugged? That it can't pick up an IP address? Or do all the network settings look fine, but you simply can't connect to the device at the other end? What are the IP settings you are using? If you are using DHCP on the PC then unplugging the uplink could well be unplugging the DHCP server too (in small setups the modem is usually acting as the DHCP server). If this is the case you could set a static IP address on the PC and the other network device. They should then be able to communicate with each other through the hub (use the ping command to test). If you want to remove the switch and go direct then the straight-through cable won't work - you must use a crossover cable in this instance (and must set static IP addresses since you won't have a DHCP server). Most switches these days auto-sense straight-through and crossover cables so you can use either when going through the switch (I'm assuming you have a switch and use the term 'hub' interchangeably. If it really is a hub you will need to use a straight-through cable).