Make/Model	Device Version	Connection Type
Polk/XRt12	N/A	Serial

Description:

This driver supports the Polk XRt12 XM radio tuner. This tuner provides a simple serial protocol that provides some feedback on current channel, artist, genre, signal strength, etc..., and allows for channel selection and a few other controllable parameters.

Quirks and Limitations:

We've noticed some seeming inconsistencies in the implementation of the protocol in older versions of this device, which would make this driver unable to control it. But for any recent version of the device the driver should work.

Connection Details

The Polk uses a serial connection at a slow 9600 baud, 8 data bits, no parity, 1 stop bit. The protocol is actually fairly wasteful for such a slow connection, but it does well enough given that the data doesn't change rapidly anyway.

Driver Fields

This section lists the fields that the driver makes available, their types, minimum and maximum values, etc...

Name	Type	R/W	Description/Limits
CategoryName	String	R	The name of the category of the currently playing song.
ChannelNum	Card	R/W	Read this field to get the currently playing channel number. Write to it to select a new channel.
ChannelName	String	R	The name of the currently playing channel
CurArtist	String	R	The name of the currently playing artist
CurTrack	String	R	The name of the currently playing track
Mute	Bool	W	Write true to put the Polk and write false to unmute
Navigate	String	W	Allows you to drive the menu navigation and to move up and down in the channel and category lists. This is an enumerated field with the values: Enter, Menu, CategoryRight, CategoryLeft, SelectUp, SelectDown, Jump
Preset	Card	W	Write to this string to select a particular numbered preset from 1 to 99.
SignalQuality	String	R	A text description of the current signal quality