I've been trying to make this combo work from an MSC-400 for about a week now, but no luck!

Heres the link to the info sheet

[Link: pioneerelectronics.com]

I have it wired with a crossover cable at 9600 (Have tried without crossover and at 115200)

Power on should be ...

/A181AFBA/RU

Tried this with and without carriage return... NO LUCK

Let me know if you've been able to make this work/have some advice

I have not controlled one via URC, but I did integrate a Pioneer BD player, I can't remember the exact model as we are not Pioneer dealers, with a RTI control system recently and used the command /A181AFBA/RU\r to power on the unit. This is of course an ASCII command and the parameters were 115200, 8, None, and 1. I can't remember if it required a straight or null connection, but that should be relatively easy to check with a simple adapter. I also think I updated the firmware first as there might have been an issue with RS-232 control without the update. Hope that helps.

You must do the most recent firmware update for RS-232 to operate. Download it from the BDP-31FD product page at pioneerelectronics.com
then unzip the file to a "clean" USB and follow the players on-screen instructions. You could check using the 31's metwork connection but the download file from that site had not been updated as of last week.

Ill try the firmware update now, I tried updating over the network and just assumed there wasn't one when it said everything was fine

I'll post again with results.