hold 'up' arrow while powering on to access interface setup area. Modbus unit ID, baud rate, BT pin etc. Press 'set' twice in succession to exit. note: baud rate 2400 & 19200 does not appear to work.

select baud rate (must match hardware configuration) select slave address (must match hardware configuration) Connect - automatically searches and connects to port (button status shows 'Connected' or ...