The D-SUB 15-pin to Terminal Block Adapter (EA-COMCON-3) is used for "daisy chaining" RS-485 or RS-422 connections and conduit cabling - where the end of the cable must be removed in order to run the cable through a conduit or other size restricted opening. Dimensions of the adapter and of a 6" panel with the adapter installed are shown below. The increase in panel mounting depth of 0.687 inches is consistent across all C-more panel sizes.