A rollover cable is a special cable used to connect
to the consoles of networking devices.
It allows you to connect from the serial port on your PC or laptop
to the console of a router or switch.
So if you've got a serial port or COM port on your PC
you can connect directly to the console of a router or switch using a rollover cable.
However a lot of modern day PC's don’t have serial ports
so you’ll need to get a USB to serial port converter
which has a USB connection on 1 side and a DB9 male connector on the other side.
This would allow you to connect DB9 female console cable to your PC
with either a Rj-45 connector on the other side or another DB9 connector.
Most Cisco switches and routers use an Rj-745 connector
but you may come across some devices from other vendors such as HP
that use a DB9 connector for the console port.
So a DB9 serial would connect to your PC and either an Rj-45 or DB9 serial
would be connected to the console of the networking device that you want to configure
in a rollover cable all pins are inverted or rolled over.
So pin 1 is connected to pin 8, pin 2 is connected to pin 7, 3 to 6
and so forth and so on until you get to pin 8 which is connected to pin 1.
You could use a standard Cat5 or Cat6 cable as a rollover cable
and then just change the pin outs on the ends from straight through to rollover but
typically this is not required as most networking devices are ship with console cables.
This video has explained a lot about Ethernet and data flows, in the next video
we'll look at how traffic is forwarded by hubs, bridges, switches, and routers.