Find out who's at your door via your household phone by using this Channel Vision Telephone Entry Controller in conjunction with an IU Series or DP series door station intercom. From the convenience of your couch, bed, kitchen, or anywhere you have a standard phone line installed, you can speak to visitors at your front door. By adding a door strike relay and an electric door strike, each sold separately, you can even grant entry access to the front door by pressing a touchtone code on your phone. When guests (wanted or unwanted) push the button on the intercom the phones in the house will send a distinctive ring. Simply pick up any telephone handset and press "#" or "*" twice to begin speaking to the visitor. Now you have the power to choose whether or not you want to see who's at the door and whether or not you want to let them in.This system requires an intercom unit. These intercom units integrate a weather resistant speaker/microphone, and doorbell button. Units are available in several colors to match your home's dcor. IU Series: Oil-Rubbed Bronze Satin Nickel Brass White DP Series: Antique Copper