Yes, if your TV set has a QAM tuner and you subscribe to some kind of TV service. The TV signal is not enabled if you have only Internet or Phone service.
Verizon transmits some channels in the clear. Usually these are the local channels, local HD channels, Univision and WGN. Otherwise, the channels are delivered encrypted and need a set top device of some sort to decode them. See this FAQ for more details. »Verizon Online FiOS FAQ »Does FiOS-TV require a set-top device?
Do not confuse a set top box with a Digital TV Converter, which is a device that enables older televisions to show the newer over-the-air digital broadcasts. FiOS-TV signals are not compatible with those devices.
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