No need to set any cables, immediate use once set-up in a few minutes When comer presses the doorway camera (transmitter), the indoors monitor (receiver) will automatically turn on with "DINGDONG" sound. At the same time, the house-owner/user can see clear image of the comer on the receiver and talk to the comer. ) When no comer, the indoors receiver can be used as a 2.4GHz wireless security monitor, which can receive A/V signals from up to three 2.4GHz wireless cameras. User can buy additional 2.4GHz wireless cameras from our company. When no comer, user can view the doorway scene transmitted from the doorway camera by pressing the CAMERA button on the indoors monitor.