You can certainly use a coax splitter for internet connectivity. If installed correctly, a cable splitter will not cause any problem with your internet connection. Splitting coaxial cable for the internet and TV is done by many people worldwide. A coax splitter is primarily meant for TV cable signals. However, many people use it for internet connections as well. An ADSL Splitter works very well for connections that carry the phone line and DSL signal as well. Moreover, it filters high frequencies that are generated from phone lines. If you do so, you need to take care of the stability of the internet connection. Also, you need to take care that every channel gets a usable bandwidth. However, if you do not have a physical phone line for your internet connection, you might not need a splitter. Moreover, any digital signal does not require the use of any sort of splitter.