Every Cisco router contains a console port on its back. It is there to provide a technique to connect a terminal to the router in order to work on it. The console port is used by administrators to log into a router directly — that is, without a network connection. The console will be used to install routers in their networks because, certainly, at that point there is no network connection and work.

Long term, the console is to have a possibility in case of emergency. When a router is completely down - in other words, when no longer capable to process network packets - can be accessed through the network. If the router is up and processing packages, but part of the network through which the technician must have access to the system is down, this is a network to determine the router is not an option. This is when the console port provides a sure way to connect to the router to fix things. The drawback, of course, is that somebody should be in the same physical place as the router in order to connect to it.

Console Terminal Types

A stand-alone CRT, computer or system can be utilized as a console. Console terminals should run a character-based user interface. They cannot run a graphical user interface (GUI) for example Microsoft Windows, Mac Operating System, or X-Windows. In order to use a computer or system as a console, you must apply terminal emulator software. For example, one of the best-known terminal emulators is HyperTerminal from Hilgraeve, Inc., which ships with all versions of Windows.

Console Connector Types

Console ports in Cisco routers use a range of connector types (25-pin, RJ-45, 9-pin, and so on), but all give a single terminal connection. A word of warning: make confident you have the proper cable before trying to connect a console terminal to work on a router. A lot of a network administrator has spent a half hour deception with cables to finally find one that could connect to a router just to do 15 minutes of creative work.

The Auxiliary Port

Most Cisco routers have a second port on the back called the auxiliary port (typically called the AUX port, for short). Like the console port, the AUX port makes probable a direct, no network connection to the router.

How does the AUX port be different from the console port? The AUX port uses a connector type that modems can plug into (console ports have connectors designed for terminal cables). If a router in a distant data closet goes down, the network administrator asks someone in the area to go to the router and plug in a modem so it can be serviced remotely. In more complicated configurations, a modem is often left permanently connected to a router’s AUX port. Either way, the AUX port gives console-like access once it is not practical to send a technician to the site to work on a router through a local console. Picture 4-6 shows the console and AUX ports on the back of a Cisco 4500 router.