1. Use HDMI cable: If the living room projector and TV have HDMI ports, you can connect them with HDMI cable. Plug one end into the HDMI port of the TV and the other end into the HDMI port of the projector, and then turn on the projector and the TV. This method can use the projector and TV as the screen at the same time, and switch as needed.

2. Use VGA cable: If you don't have an HDMI port on your TV or projector, consider using VGA cable to connect. Plug one end into the VGA connector of the TV and the other end into the VGA connector of the projector. This method needs to turn on the projector and TV separately after connection, and manually adjust the screen when using.

3. Use RCA cable: If the projector and TV don't have HDMI and VGA interfaces, consider using RCA cable connection. RCA cable, also called AV cable, connects one end to the video interface of the projector and the other end to the video interface of the TV. Then the other two RCA lines are connected to the audio output port, one is connected to the left and right channels of the projector, and the other is connected to the left and right channels of the TV, so that sound can be output at the same time.

It should be noted that no matter which connection method is adopted, the input sources of the projector and the TV need to be set according to the situation, otherwise the output signal may be abnormal. At the same time, different connection methods have different effects on image quality and sound, and users can choose the connection method that suits them according to their own needs.