Final answer:
A cable splitter is the tool required to separate cable TV from the home network during the setup of a cable modem, allowing for simultaneous use of both services.
Step-by-step explanation:
When setting up a cable modem to separate cable TV from the home network, the tool required is a cable splitter. This device is specifically designed to divide a single cable signal into multiple paths and direct them to different devices, allowing for both cable TV and internet services to be used simultaneously without interfering with each other. A cable splitter typically has one input for the cable line that comes from the cable service provider and multiple outputs for connecting to various devices, such as a cable modem and televisions.