The problem with most intercom relay systems is that they often require a professional hardwired installation and only work with a single landline based home telephone. This door phone access control system uses GSM Quad Band technology for communication, allowing wireless communication not just to a landline based home telephone but to any landline based phone or cellular phone as well. An external GSM antenna is included for clear reception; the antenna is attached to 16 feet of cable. Additionally, this device is flexible enough to work for home or commercial applications as up to 263 subscribers can be registered with the system. Each subscriber is given a unique subscriber number (from one to six digits) with two different phone numbers to answer a visitor's call. The unit also features an LED back light that will automatically turn off after 30 seconds, conserving energy consumption. This plug-in device can be wall-mounted or flush-mounted, as it is built of a rugged, weather-resistant aluminum alloy exterior casing, ideal for outdoor installations. This access control system can be connected to a electronic door strike/lock as well as a single or double automatic gate opener, each sold separately. When a visitor arrives at your property, they simply dial the subscriber they are trying to reach, and whether or not that subscriber is on site, at the office, or on vacation halfway around the world, they will be able to grant access and unlock the door or open the gate at the press of a button. The unit features a full size keypad and a large LCD display for easy programming by the system manager and easy operation by visitors. The system manager can set three emergency phone numbers and enable or disable subscriber functions.Other Applications # For your home office or small business - The GSM Quad Band Wireless Door Phone Access Control System. It is ideal for home or small business use. Many office buildings require that the main entrance be closed all the times for security purposes. The device can act as the wireless entry system for this application. Once installed, an employee or visitor can simply enter the office suite number on the keypad which will alert the receptionist who can then allow them to come in. The unit also has the capacity to unlock a door by keying a number code. Additionally, if you are away from the office or meeting with a client but are expecting an important package from UPS or FedEx, the driver can press the call button, and you can remotely open the door. # For real estate - The GSM Quad Band Wireless Door Phone Access Control System is great for realtors who have many homes open for viewing. Instead of making long trips back and forth from the office or if you are running late, you can grant a prospective buyer access to a home remotely. Once you have set an appointment, advise your client to use the system to contact you via the access control system and you can let them in. The buyer can even contact you via the device to talk to you and ask questions.