Only thing is that this unit was designed to be connected with the weird Tip Ring Sleeve scheme where one jack would serve as both send and return... like on the old Mackie Board.
The manual does state that you can connect up to other equipment but you must use Tip/Sleeve unbalanced cables... but I'm not sure if connecting Tip/Sleeve cables to TRS balanced ins/outs on 828es will work. Here's pertinent section from the manual:
HOOK-UP
The RNC is designed to interface with unbalanced audio gear (nominal operating level = 0dBu) two distinct ways:
1) TRS Inserts — The RNC can be hooked into Tip-Ring-Sleeve (TRS) insert points found on many consoles where: TIP = Console insert out, RING = Console insert in, SLEEVE = Ground reference. This means that each channel of the RNC can be hooked to a each channel of a TRS console insert with a single TRS cable. For example, on my Mackie 1604VLZ, the main out has left and right insert points so that my RNC can be put in the main out insert (Left and right) with only two TRS cables!
20 All Other Equipment — Hooking up the RNC to gear other than TRS inserts must be done with a pair of TS (Tip-Sleeve) jacks for each RNC channel. Thus, the full ste- reo hook-up of an RNC must be done with four TS 1/4'' cables.
NOTE — Hooking up the RNC to balanced lines with TRS 1/4'' plugs will not work! If the equipment you are connecting the RNC to is balanced, you must first unbalance it and only connect into the RNC with TS 1/4'' plugs.