Multiple USB Devices in Pro Tools

If I have 3 seperate USB I/O devices in Pro Tools, (Fast Track USB, Line 6 Tone Port, USB MIDI 49e) should I be able to use these simultaneously and should I see any performance impact?

USB devices are a little unpredictable, in my experience -- some will work just fine through a hub, but some must be plugged directly into the computer USB port. i have no idea why or what that means, but it's popped up with my gear a couple of times.

The short answer is No.
The long answer is 'No, you cannot'.

For a start, You can only use M Audio or Digidesign interfaces with protools.
Also, you cannot interleave the interfaces to form an aggregate device like you can with Core Audio.

You CAN run one protools interface and still have the others plugged in, for other applications, like Peak, Ableton Live to access but I guess this isn't what you are asking.

If you need up to 16 IO you need a 002 or 003 and an external analog-adat converter.

More than 16, you need Protools HD (which is what I use).

Thanks, Jim. I suppose I have enough work cut out for me getting to know my way around Pro Tools with 1 in for now. My cousin (16 years old) encouraged me to make the leap to Pro Tools. He's working out of his own studio with an 003 & Pro Tools LE. He's really harnessed a lot of power and is getting great sounds for his own band and quite a few others. I'm still as intimidated as hell by it, but it's probably due more to limited understanding of audio engineering.

Thanks, Jim. I suppose I have enough work cut out for me getting to know my way around Pro Tools with 1 in for now. My cousin (16 years old) encouraged me to make the leap to Pro Tools. He's working out of his own studio with an 003 & Pro Tools LE. He's really harnessed a lot of power and is getting great sounds for his own band and quite a few others. I'm still as intimidated as hell by it, but it's probably due more to limited understanding of audio engineering.

No worries.

If I can assist you at all, let me know.
Think of Protools as a word processor for audio- it is very flexible in how it manipulates audio - and often there are various ways to perform the same task.
I still maintain that Logic is far superior for composition and arrangement... and midi.
But for editing and mixing nothing beats protools.
Elastic audio (in V 7.4) has dramatically changed my workflow.