7i90 via RS422 setup information, is serport used?

I am looking into various ways to make use of the 7i90's I have. I have completed hooking them up EPP on both a native parallel port and PCIe parallel port cards, completed SPI on a Raspberry Pi, and now I am looking to understand how to connect with LBP16 over RS422 (better isolation for plasma work). 

I have the RocketPort Express octa card setup and configured for RS422 and am able to set the address for it in the serport module. But it looks like the serport module is for RS232? and I see no setting for baud? The PCIe card I have is good for 921K baud / RS232 / RS484 / RS422 and has 8 ports. 

I have been unable to find ANY mention of someone using the 7i90 with RS422. Can someone shed a little light about using RS422+7i90hd+LinuxCNC in a realtime application?

It seems this could be a useful setup to have a pair of 7i90's, multiple RS422 digital IO boards, comms to the servo drives, etc, all nice and isolated over differential pairs. 

There is currently no LinuxCNC support for serial Hostmot2 cards
(it has been used for other applications including a 72 channel/card scaler/counter for a CAT scanner but not LinuxCNC)

Ah, thank you. I was starting to think my google was messing with me or something

Out of curiosity would the 921K have been fast enough for real time operation? I saw a few higher baud boards but I think they were talking about the speeds of their mPCIe slots, not the RS422 speeds.

I am glad to have the RS232/RS485/RS422 card for generic PLC driver boards and the like which work with ascii commands anyway.

Probably 2.5 or 5 Mbits/sec would be a minimum for a 1 KHz servo thread
(Typical data transfer size is around 500 to 1000 bits)