Designed to replace older 3-wire or 4-wire intercom systems, the NuTone NM100 Music Intercom Master Station (White) offers a retrofit system for whole-home music distribution and intercom communication. Connect as many as 15 remote stations to the 4-wire model, or 13 stations to the 3-wire model, as well as three door speakers for either model. Then start streaming audio throughout your entire home! This retrofit master intercom station serves as the main hub of your home's NuTone intercom system. Two music source inputs allow you to connect any external music source, such as an iPod. The station also features a built-in AM/FM radio with eight AM station presets and eight FM station presets. A comprehensive menu of settings is easily accessible via the station's backlit liquid crystal display, which shows the volume setting, audio source, operation mode, radio frequency, and time. You can set the system to automatically turn music on/off at specific times, so you can kick off the day or wind down at night with automated music for your convenience. The NuTone NM100 Music Intercom Master Station also has a door release mechanism for use with an electric door strike (sold separately). Turn your intercom into your personal security assistant and gain peace of mind! When you replace your old master intercom stations, you will also need to upgrade the old intercom stations located around your home. All NuTone NM100 remote stations (3-wire and 4-wire) connect to the master station using your existing wiring. These stations have simple pushbuttons that control the system remotely. To install the NM100 Master Station alone, order the NuTone NM Series Rough-in for NM100/NM200 Master Station (NWH300).