Given devices where pins 1–2 are RX and pins 3–6 are TX and no auto MDI-X is available, which Ethernet cable type is required to connect a router and a switch?

A straight-through cable is used to connect devices of different types, such as a router (Layer 3 device) to a switch (Layer 2 device). In this scenario, the router's transmit (TX) pins connect to the switch's receive (RX) pins, and the router's RX pins connect to the switch's TX pins. This direct connection is achieved with a straight-through cable because the internal wiring of the devices handles the transmit/receive roles. A crossover cable would be used for connecting like devices (e.g., switch to switch) or when both devices use the same pin assignments for TX/RX. Rollover and console cables are used for device management, not for network data transmission.