OK, so exactly what are you trying to do, get information from the 585 like depth to the 4000 series garmin chart plotter, or get informaiton from the 4000 series to the 585 like long,lat, disteance to next ?? or both
The 4000 has 4 NMEA0183 inputs and 2 NMEA0183 outputs,the 585 I believe has two NMEA0183 ports configured as input/output ports, but can be changed to input/input through the menu.
After wiring both units need the NMEA ports selected to be properly configured in the units menu.