Cisco Networking: Connection via Rollover Cable
You most likely make your initial configuration of your Cisco device through a direct serial cable connection via a Cisco rollover cable — the strange blue cable you get with each of your managed devices, as shown in the following illustration.
To use this cable, you need to have a 9-pin serial port on your computer; otherwise, you need to use an adapter. These days, many laptops and desktop computers are legacy-free; they do not have any legacy computer ports. This includes PS/2 keyboard and mouse ports, parallel ports, or serial ports.
This can slow you down a bit when trying to configure your Cisco device. Luckily, a large market for manufacturers of USB adapters, such as the serial adapter shown in the following illustration, exists.
Not all adapters are created equally, and sometimes adapters have not worked with some devices. Get a good price, but do not go cheap. To some degree, you do get what you pay for.
After you have a place on your computer to connect the cable, look on the device for the console port. On most Cisco devices, this is blue and labeled RJ-45 connector, as shown in the following illustration. If this is a 9-pin serial connector, you are dealing with a very old device.
Connect your computer to the console port on your Cisco device, which may even already be running. To complete the connection you will need a terminal emulator application like PuTTY.