[R3altruth]

Pro Tools has 3 versions.....All of which are PC or MAC compatible

Avid Digidesign Pro tools|HD uses PCI (or PCI express "PCIe") cards that connect to DIGIDESIGN interfaces..... using internal cards gives you the advantage of being able to record many tracks at once... and at a very high quality... with tons of processing power right on the cards... Taking a lot of the load off of your processor. Back when computers were very slow, DSP cards were the only way to record on a computer.
Uses TDM (Time-division multiplexing) for plugins and to communicate between hardware
There are 3 basic components to a pro tools HD system....
1: The cards (1, 2 or 3 PCI or PCIe Cards)
2: Digidesign PT|HD interface (Connects directly to the cards and provides the I/O for your system)
3: A control Surface wich uses its knobs, faders and Transport (Start, Stop, Record, etc...) to control functions within Protools
Digidesign makes Control Surfaces (Control 24, Icon D-series) for use with PT|HD
Many Large scale consoles serve as a control surface for pro tools as well as having channel strips that provide a preamp, eq, and compression.....


Pro Tools LE - (RTAS Real Time Audio Suite) plug ins
pro tools LE is the version of Pro Tools that comes with any MBox or Digi 003...
They both do three things....
1. They allow you to use pro tools.... If you go to load up pro tools LE with neither one of these (Or a previous model such as the 002) hooked up, Pro Tools Le WILL NOT START...
2. They let you record in through various inputs
and 3. they let you listen to any audio with several outputs that can go to speakers or headphones

Let's look at the hardware...
the Digi 003 comes in 2 forms.. the rack and the console...
both have 8 analog inputs... analog meaning an XLR or quarter inch cable.... 4 of those can use both.. and 4 only allow a quarter inch connector.... a noteworthy piece of info... Phantom power (the power used by large diaphragm condenser mics) can only be used by 2 XLR inputs at a time.... There is the ability to go ADAT input, which is a digital input that allows for 8 channels to be sent over 1 "Light pipe" optical cable... The console version also has a handy control surface with 8 motorized faders... a jog wheel and transport (start, stop and record) controls....
They are both firewire so there is very little to no latency and the work with either Mac or PC.. the console runs you about $2200 while the rack version is anywhere from $1200 to $1400....
The Mbox... which is in it's second hardware generation uses the exact same pro tools software (Pro tools LE) as the 003....
The MBox 2 comes in 4 different versions.... None of which has any type of control surface....
the MBox 2 Pro.... which is a firewire interface which, for $700 gives you 4 inputs (2 of them are mic inputs), and 6 outputs...
The Mbox 2 gives you 2 ins and 2 outs through a USB cable for $450
The MBox 2 Mini is a cute little $300 USB interface that gives you 1 mic input, 1 1/4 inch input and 2 outs... Just so you know, 2 outs means it can go out to 1 pair of speakers...
and lastly.. one of the most innovative and well thought out...
The MBox 2 Micro is essentially a handy little $250 USB Pen drive.... that allows you to use Pro tools LE on your system... it IS the interface.... although all it has is a headphone output....

Pro Tools M-Powered
Avid is the company that owns Digidesign... a few years ago they acquired M-Audio as well... Pro Tools software needs a Digidesign hardware attached to it for it to run... so Pro Tools M-powered was designed to run along side the M-audio interfaces... M-powered is dangerously similar to LE... and really only exist for copyright and licensing reasons so people can use pro tools with the newly acquired M-audio stuff.....

Newest version... Pro tools 8....
Notes: LE and M-powered require special toolkits that will increse your track count past 48 as well as offering 7.1 surround support and other extras... the toolkits prices range from $400.00 USD to $2000.00 USD