you can use .NET sockets for low level access to network. you can send and receive any data you want from/to any port on any IP. unity's built in networking is a system for connecting games together using raknet networking library.
for more information about .NET sockets see these links.
MSDN reference for System.net.socketsa small tutorial by O'Relly media
So, with this I could receive datas in real time from another PC which is processing analog signals and generating a great amount of datas in real time (in order to plot a math graph for instance).