
THE FRONT
The plethora of ports found on the MusicXPC begin right on the front panel. Starting from left to right the ports are as follows:
Microphone Input: You can record audio straight away using the CD quality analog microphone input. OK, we'll admit that the latency is not as lightning fast as a professional audio card, but you don't have to buy a piece of hardware to record an audio signal.
Two USB 2.0 Ports: Capable of a blistering transfer rate of 480MBPS, these ports allow for the connection of high performance storage devices and high definition audio devices. We have tested audio hard drives connected to these USB 2.0 ports and we can report that they are fast enough for large audio production with scores of audio tracks.
The next major wave of USB 2.0 products will be high-definition [24/96/192] audio interfaces that connect to the computer solely through USB 2.0. We can't say enough about the tremendous power available to the audio professionals via USB 2.0.
THE BACK
The back of the MusicXPC has SPDIF input and outputs, 2 more USB 2.0 ports, 1 more 1394 ports, 6 channel analog output for surround/home theatre applications and more.
Optical Digital input: This port allow the recording of digital audio directly to the hard drive from an audio interface. You can use this to complete audio transfers to your MusicXPC from a digital recorder. This port uses the new cap-less connector so you won't lose your optical covers anymore.
FireWire: This is the main 6-pin FireWire® 400 port. This is ideal for connecting your FireWire interfaces like Digidesign's Digi002 and M-Audio FireWire 410. This port has power so it can power most of the smaller FireWire interfaces that do not need to be plugged into AC power.
COAX Digital output: This port allow the streaming of digital audio directly from the hard drive to an audio interface. This is for devices with COAX digital inputs like audio interfaces, DAT machines and hardware digital recorders. For most MusicXPC users the digital I/O that will be used will be on the audio interface.
Line In: This port is designed for recording analog signals coming from most devices. It records at sampling rates up to 48KHz and is ideal for transfering audio from casettes, DJ mixers, etc. for audio restoration applications.
6 Channel Audio Output: The MusicXPC comes with audio capabilities that are not usually found on personal computers. The high quality 6-channel Audio Output for connecting to 5.1 surround-sound speaker systems. This means that right out of the box you can listen to material without a sound card being installed. Now let's be clear, this is not professional quality audio but the quality is perfectly good for monitoring purposes. Certainly, you will need a high quality audio interface for serious work. 
Ports on the back of MusicXPC C4
