Straight through cables connect pins 1 and 2 (transmit) on an MDI device to pins 1 and 2 (receive) on an MDI-X device. Similarly, pins 3 and 6 are receive pins on an MDI device and transmit pins on an MDI-X device. The general convention is for network hubs, bridges and switches to use the MDI-X configuration, while all other nodes such as personal computers, workstations, servers and routers use an MDI interface. Some routers and other devices had an uplink/normal switch to go back and forth between MDI and MDI-X on a specific port.