Problem with multiple DBH setup


Active Member
After my post here, I went with a mutliple DBH setup to simplify wiring. However, its not working with the first thermostat. Any ideas?

I have connected:
DBH1 in the enclosure with the ELK.
  • Keypad 1 in position 1
  • Crossover Cable to DBH2 in position 2
  • Terminating resistor in position 3
  • Serial Expander connected to RCS Thermostat
  • Terminating resistor
Can you only use position 9 to extend to a new DBH?

The serial expander has power but the status light just flashes. I didn't see any info in the documentation on what this means or what a normal state is.

Any ideas?
ok, so I figured out on dumb thing of having the RS485 bus termination jumper set on the Serial Expander. I removed that and the ELK now find the expander fine. But when I try to see the thermostat from the keypads I just get a message that it is "Not Enabled". I followed the steps in the install doc so I don't know what's missing now ;)

Is there any way to 'explore' the serial exander to see its state and if its communicating with the TR40 control unit?