If you want to have computer controlled satellite radio you need a receiver like the XMDirect or XM Commander (both are the same thing basically, the XMDirect is cheaper!)
The XMDirect is a XM receiver in a small metal box. You connect it to your computer with a simple cable that is easily made (mini-din to standard 9-pin serial port, pinouts can be found here:
http://www.mp3car.com/vbulletin/hardware-development/36040-xmdirect-cable.html) The control protocol is very simple and well documented. Connect the antenna and provide 12v power and you should be good to go. The XMDirect is a little different from other XM receivers in that it must be sent a special "wakeup" command first before it will accept any other command. Most CarPC software has been modified now to do this.
(FYI: The XM receiver module uses a standard control protocol, receiver manufactuers simply take a XM receiver module and build around it. Anyone with a little technical skill can turn practically any XM receiver into a computer controlled receiver since they all have the same basic module inside. The XM protocol was discovered because XM released a computer based receiver called the XMPCR. Someone just sinffed the data traffic going to and from it, the rest was history
)
As for Sirius satellite radio, no one has reversed the protocol on any of the Sirius units yet. They have figured out how to get title info on some of the portable and home receiver units, but thats about it.
Linear Mode
