Upgrade your home's outdated intercom system with the IST RETRO Music and Intercom System Kit (4 Rooms, Horizontal Frames). This unique system replaces pre-existing 3, 4, or 6-wire in-wall intercoms without requiring drywall repair or new wiring. Once it's installed, you will have a full-featured music and intercom system that interconnects four rooms of your home, as well as the front door and your Master Station (expandable to 13 door/patio stations and 2 door stations total). The kit comes with a Master Station, four Room Stations, and one Door Station. The Master is the main station and distribution hub. It allows you to communicate with and play music through any and/or all stations in the system. Master Station: Retrofits into the hole of your existing master unit. Optionally supports external speakers. Features AM/FM radio with 10 presets, dock for MP3 players and other audio sources, USB/Firewire ports, and optional door release. Room Stations: Each allows you to play music distributed from the Master and communicate with other stations. When a call is initiated, all stations are paged. When the call is answered, the conversation becomes private to the two stations involved. You can also use any Room Station to listen in on other stations. Door Station: When a visitor presses the doorbell button, all stations produce a chime. You can answer from any station. The system comes with adapter and cover plates to retrofit new stations into existing holes where old stations were installed. These plates cover space left by old stations, eliminating the need for drywall repair. The included Horizontal Room Adapter/Cover Plate Kits are designed to cover space left by horizontal room station holes, meaning holes that are greater in width than height. KIT: Master Station (RETRO-M); Door Station (RETRO-D); (4) Room Stations (RETRO-5R); (4) Horizontal Room Adapter/Cover Plate Kits (RETRO-5RH); Master Station Cover Plate (RETRO-MTP); Bluetooth Receiver (BT-Receiver); Screw