I recently passed CCNA, and decided it would be fun to have few Cisco devices around for further practice.
I would like to pass CCNP in some time, and I’d really like to know what I’m doing – the labs and simulators don’t quite cut it for me.
So I started with buying two switches off ebay. They were sold without the console cables – a crucial connection for configuring Cisco devices.
From my point of view a cable is an arrangement of connections between two sockets. Switch side is RJ45, and the other side is usually a DB9, since the link carries regular serial port data. I went to a nearby electronics store, and was just fortunate enough to find a small case enclosing RJ45, DB9 and possibility of randomly wiring them up! I got two units and I googled up the cable schematic.
The official documentation at cisco.com ( console to serial cable ) shows you a nice table, but I got it wrong the first time. The first RJ45 column gives the order of pins as used by a “Rolled over” cable, so if you produce one, you won’t be able to connect your DB9-to-RJ45 between a serial terminal and the console port with a straight-through RJ45 patchcord – which is a very convenient feature. That’s what I did, and then I also needed to make a rolled-over cable.
I produced the next adapter using the second column, and it works with a straight patchcord. This is how the converter looks from the other end: