Slurm is a generic Network Load Manager which shows device stats with the help of ASCII graphs. Some features of slurm include:

• Realtime traffic statistics divided into incoming and outgoing
• Optional combined view
• Can monitor any kind of network interface (testers welcome!)
• Shows detailed statistics about the interface.
• It’s themeable (since 0.3.0)

Website: http://www.wormulon.net/projects/slurm