A coupler for an excavator, the coupler having a body with first and second spaced-apart recesses for receiving respective pins of an excavator attachment. The apparatus includes an interference detection device which detects that interference occurs in the first channel among the two first channels, and a frame generation unit which generates a notification frame that recommends the use of only the first channel width. At least one task menu specific to the object class selection is provided. A securing member is delivered through a passage in the first extender. When the connection board connects the first detection board, the first signal contact area is electrically connected to the first contact area.