You can only have 16 active I/O per interface at any given time. The maximum per HD/Accel card is 32-I/O done by having a 2nd interface connected via the expansion port on the first device. That's it!
The 192HDs that we have (and there are 3 for sale if you're interested) have 2-AES cards as well as the built-in analog I/O. You may use variations, i.e. feed analog out 1/2 as well as AES out 1, which is how we used it.
Setup within PT still sees it as ONE OUTPUT, yet you're feeding an analog and digital hose with the same signal. You can't have 16-AES outs and 8-analog outs selectable from different sources.
(Hardware for sale at
http://duc.avid.com/showthread.php?p...86#post1983186)