There was a need to connect to a single network outlet, multiple devices, and the simplest solution was purchased this "miracle of technology". Immediately began a completely unexplained phenomenon.
Starring: a computer that obtains an IP address using DHCP, IP camera with fixed IP address and the cable which connects the switch with the socket on the wall. At the other end of the socket is Cisco 2960. If the switch is enabled at the same time, and PC camera, the PC cannot obtain the network address from the DHCP server. Tried instead of the camera to connect a second PC (also a DHCP) address from the server gets only the computer that is turned on first. Included second the server sees. And so in all possible combinations.
Changed my mind now all the options.
What might be assumptions you habradi?