just to add to what Eric has already said..
most routers come with the interface access settings on the back of it..
i.e. it may say
URL: http:\\192.168.0.1 (or 192.168.1.1 or 192.168.1.254)
USERNAME: admin
PASSWORD: admin
you would type the 192.168.1.1 or whatever it is into the address bar in your web browser and press enter - this takes you to the routers login screen, then you log in with the stated details - then one would look for something along the lines of 'Connection Stats' or 'Router Status' - something that indicates stats, one simply has to browse through the sections until they find them
you want Connection Speed, Line Attenuation and Noise Margin