Dual-Way communication between monitor and camera, monitor and monitor; support call transfer among all the monitors. You can answer the door and unlock via all indoor monitors, it is convenient and widely used in apartments, villas, hotels and offices. Multi-device interconnectionSupport connect with additional 2x CCTV camera, 2x PIR alarms, 2x electronic locks, giving you more comprehensive protection for your home. About the extension wireThe extension wire is not included in the box, but we will provide the 4 pin connector for you connect the extension wires.You can use RVV4(4 core wire)/Cat5/Cat6 wires to extend the distance for monitor to doorbell, monitor to monitor according to your need, maximum distance 100-200 meters. We pride ourselves on friendly customer service and are always happy to help with any questions or queries. In the unlikely event you are unhappy, please get in touch before leaving feedback and we will try and resolve your issue. The item "TMEZON Video Door Phone Doorbell Intercom System, 1080P Door Entry System, 7" is in sale since Saturday, March 6, 2021. This item is in the category "Home, Furniture & DIY\Home Security\Door Entry Systems & Intercoms".store" and is located in LS15 8FP, Leeds. This item can be shipped to United Kingdom, Antigua and barbuda, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Australia, United States, Bahrain, Canada, Brazil, Japan, New Zealand, China, Israel, Hong Kong, Norway, Indonesia, Malaysia, Mexico, Singapore, South Korea, Switzerland, Taiwan, Thailand, Bangladesh, Belize, Bermuda, Bolivia, Barbados, Brunei darussalam, Cayman islands, Dominica, Ecuador, Egypt, Guernsey, Gibraltar, Guadeloupe, Grenada, French guiana, Iceland, Jersey, Jordan, Cambodia, Saint kitts and nevis, Saint lucia, Liechtenstein, Sri lanka, Macao, Monaco, Maldives, Montserrat, Martinique, Nicaragua, Oman, Pakistan, Peru, Paraguay, Reunion, Turks and caicos islands, Aruba, Saudi arabia, South africa, United arab emirates, Ukraine, Chile, Bahamas, Colombia, Costa rica, Guatemala, Honduras, Kuwait, Panama, Philippines, Qatar, Trinidad and tobago, Uruguay, Viet nam, Russian federation.