Dell KVM 1082DS - Manual (Page 42)

32 xxx | Installation xxx
NOTE: The switch supports one tiered switch per target port of the main
switch. You cannot attach a switch to the tiered switch.
NOTE: When cascading with an RCS, an 8-port or 16-port analog console
switch is not supported as the primary unit in a tiered configuration. The RCS
must be the primary unit.