Although broadcast television stations have disconnected their analog signals, cable television is still transmitted to your television and cable box via coaxial cable. If you are unsure of the functionality of a cable outlet, the best course of action is to connect a known-to-be-working television with a built-in digital converter to the outlet using a known-to-be-working coaxial cable. Though this involves potentially lugging a television from room to room, it is the most effective method to determine if an outlet is active.
Connect the coaxial cable to the cable outlet. Thread the nut on the end of the connector onto the outlet until tight to secure the connection.
Connect the other end of the coaxial cable to the coaxial jack on the rear of the television. Thread the nut on the end of the connector onto the jack until tight to secure the connection.
Turn on the television and press the "Input" button on the TV itself or on the remote until the "TV," "Cable" or "Satellite" input is set. Tune to a known cable channel on the television. Be sure to tune to a cable-only channel, such as MTV, Comedy Central or Discovery. If you receive a picture, the cable connection is active.