[lancemcv]

I know I am repeating some already mentioned info by others here but seeing I have a M32r I thought I would chime in. On the more pricy config you can get a Rednet 5 pretty cheap on ebay around 450.00 as mentioned by others which will work in conjunction with your omni / hdx card acting the same as if you had two HD IOs as the Rednet 5 is 32 channels of IO into pro tools. The Red net would connect to your first digilink on your card and your omni to the second digilink port on the hdx card. Plus you need the dante card for the M32 not cheap like 600 to $700 which then connects to the dante port on the Rednet 5. You can then use all 16 pres on the M32 and your two omni pres into pro tools at the same time. Or add a DL32 stage box and get 32 pres into your system.
Keep in mind that the M32 only works at 48k and 44.1.

Now the cheap way is the ADAT card for the M32 as mentioned which will get you 8 pres from the board into the Omni but you can't use the omni pres in combination in that setup its either or.

The M32 or any X32 / M32 variation remote DAW control is limited to 8 fader banks at a time you cannot use all 16 of the boards faders, the faders are also really noisy when tracking automation at least my M32r is, like scratching up and down noise as the fader tracks the automation on playback. When writing they are very quiet, but in playback its pretty bad but usable and you can just hit the daw remote button to turn it off after you write your automation if you don't want the faders to physically playback. You also do not get a pan control in remote daw mode with the m32. You do get fader, mute, solo. transport control, record ready, track select, bank up and down in groups of 8 channels or bank up and down 1 channels at a time, There are a few more options but I have not yet messed with them that are assignable in the custom assign button section on the board.

Now after saying all that, I ditched my omni and native card and am just using the M32r. It sounds great, it has 16 pres that are remote controllable via iPad or computer and I have the stock USB card, which gives you 32 channels of io to pro tools, limited remote daw functionality via hui but not bad, I also use the Pro Tools control app with my iPad and they work well together Hui and Eucon. The other benefit is you have a mixer not just an interface, when tracking and monitoring off the board and not through pro tools, latency is a non issue as there is virtually non. The board pres go direct to pro tools, no eq or compression gets recorded, its mic pre to disk although with some trickery in the routing section you can use the eq and compression on the board and record it. There are so many great things about this little board. You can do a quick mix and spread 32 tracks across it and use the boards internal processing. You can return a pro tools session on a stereo aux return and mix in the box while also using remote daw and you can also play sound from the computer while pro tools is open and A/B something in iTunes and compare it to your mix as an example, or even at the same time not that you would want to. I often have pro tools and FCPX open at the same time and I don't have to switch to monitor one or the other. The omni you have to run an optical cable from your computer into it to monitor your computer within pro tools its a bit of a pain. Also the one usb connection gives you a midi interface, daw control, computer audio and pro tools return all over the one usb connection and it's rock solid. I do really wish it supported higher sample rates but for the money its a very cool little board. If you want 96k there is always the pro line of Midas boards and the DNS9650 network bridge with Dante.... ah I digress....