Your cable modem would go on the -3.5db leg (this is effectively 2x 2 way splitters cascaded with the 3.5dB path being one of the outputs from the 1st splitter) ...

If your business gets cable TV and high-speed internet access from the same company using the same line, you can use a coaxial splitter to connect your internet router and one or more cable boxes ...

GE Digital 2-Way Coaxial Cable Splitter, 2.5 GHz 5-2500 MHz, RG6 Compatible, Works with HD TV, Satellite, High Speed Internet, Amplifier, Antenna, Gold Plated Connectors, Corrosion Resistant, 33526 ...

A splitter reduces the signal by at least 3.5 dB, which results in two signals with less than half the power of the original. Some splitters have even more loss.

Often your local cable office, if you have one, will give you everything you need for free, splitter, extra coax cables, etc. Click to expand... Specifically, a 2 port splitter will be -3.5 dB per ...