1. we are not a switch connect the wireless camera, and can support PAL or NTSC, Support PAL and NTSC at the same time. 2. Please choose a quality camera to connect. A bad camera cannot be identified by the control unit. 3. After installation, your camera does not work, please check the quality of your camera and your connection. Thank you. 4. Four-channel car video controller with four-door partition, with a mirror switch for each camera.You can see 4 camera images in one window<br><br>Screen mode Introduction to automatic mode: (numbers the corresponding camera channel number, channel number is not displayed) (1) When 4 cameras are connected, the camera work after the car starts, and four images be automatically displayed at the same time [H type] (2) When 3 cameras are connected, the camera work after the car starts, and three images be automatically displayed at the same time [product type] (3) When 2 cameras are connected, the camera work after the car starts, and two images be automatically displayed at the same time [left/right/up and down split] Introduction to manual mode: 1. the upper left corner to turn on the machine, and the automatic split image screen be displayed. The automatic shutdown mode be invalid. again to turn it off, and the automatic mode take effect. 2. Long the button on the extension cable to turn on the machine, and short to switch the screen mode. (Long 1 second, short Less than 1 second) Working voltage: DC9V-36V Pixels:640 x 480 Material:ABS+Metal Color: black<br><br>Package Contents: 1Pcs Car 4-Channel Driving Recorder Switcher Control<br><br>Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.