I am trying to connect an FX60 to a mammoth RTU with a I/O Pro 812u. I am connecting with a 3' piece of wire from the internal RS485 card to the port2a (net+, net-). I have setup bacnet correctly and have tested with known good controllers. I cannot add this 812U manually or with discover.

My wiring is @ 812u red net+ // blk net- @ FX60 red+// blk - (no ground)

I have tried various speeds without luck. This controller allows you to choose N2 which I did, and was able to discover the device without issue when I added a N2 network. My job spec'd Bacnet MSTP though.

I have selected MS/TP MASTER and selected 2 wire/ 485 on the units jumpers.

I know the JACE is setup without issue because I can talk to a PCT controller when connected. My device network is 2001 and 812u is using 12 as the address.

Any help is appreciated.