Add NAD documentation

source/_components/media_player.nad.markdown

@@ -0,0 +1,50 @@
+---
+layout: page
+title: "NAD"
+description: "Instructions how to integrate NAD receivers into Home Assistant."
+date: 2016-01-05 20:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: nad.png
+ha_category: Media Player
+ha_release: 0.36
+ha_iot_class: "Local Polling"
+---
+
+
+The `nad` platform allows you to control a [NAD receiver](http://nadelectronics.com) through RS232 from Home Assistant.
+
+To add an NAD receiver to your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+media_player:
+  - platform: nad
+    serial_port: /dev/ttyUSB0
+    name: NAD Receiver
+    min_volume: -60
+    max_volume: -20
+    sources:
+      1: 'Kodi'
+      2: 'TV'
+```
+
+Configuration variables:
+
+- **serial_port** (*Required*): The serial port . Default is `/dev/ttyUSB0`
+- **name** (*Optional*): Name of the device. Default is NAD Receiver.
+- **min_volume** (*optional*): Minimum volume in dB to use with the slider. Default is `-92`
+- **max_volume** (*optional*): Maximum volume in dB to use with the slider. Default is `-20`
+- **sources** (*Optional*): A list of mappings from source to source name. Valid sources are `1 to 10`.
+
+The min_volume and max_volume are there to protect you against misclicks on the slider so you will not blow up your speakers when you go from -92dB to +20dB.
+You can still force it to go higher or lower than the values set with the plus and minus buttons.
+
+<p class='note warning'>
+On linux the user running home-assistant needs `dialout` permissions to access the serial port.
+This can be added to the user by doing `sudo usermod -a -G dialout <username>`.
+Be aware that the user might need to logout and logon again to activate these permissions.
+</p>
+