Which type of network connection requires a straight-through cable?

A.
host to host

B.
switch to router

C.
switch to switch

D.
host to router’s Ethernet port

Explanation:
A switch to router connection requires a straight-through cable. Straight-through cables are also used for host
to switch communication.
A crossover cable is used to connect “like” devices, and a straight through cable is used when connecting
“unlike” devices. The one exception to this rule is when connecting a computer NIC to an Ethernet port on a
router, a crossover cable is used. In summary, the following list describes when to use crossover and straight
through cables:
Host to host Crossover
Host NIC to router Crossover
Host to switch Straight through
Switch to Switch Crossover
Switch to router Straight through
The difference between straight-through and crossover lies in the location of the wire termination on the two
ends of an RJ-45 cable. If the unshielded twisted-pair (UTP) cable wire connects Pin 1 of one side to Pin 1 of
other side and Pin 2 to 2 through all eight Pins of the RJ-45 connector, the cable is said to be straight-through.
On the other hand, if the Pin 1 of one side RJ-45 cable connected to Pin 3 of other end and Pin 2 connects to
Pin 6 of other side, it is called as crossover cable. The cable type to be used depends upon circuit connection
on the hardware. Some devices have ports that are capable of identifying the cable type and automatically
adjusting the port setting to be a standard or uplink port.
Host-to-host, switch-to-switch, and host-to-Ethernet-port would all use a crossover cable to connect in the
network. The following figure shows the pin layout for a crossover cable:

Objective:
Network Fundamentals
Sub-Objective:
Select the appropriate cabling type based on implementation requirements

Cisco > Product Support > End-of-Sale and End-of-Life Products > Cisco 7000 Series Routers >
Troubleshooting Technotes > Cabling Guide for Console and AUX Ports > Document ID: 12223