An example universal contact assembly includes plug contact members and a sensing contact member that are overmolded together to form a single unit. Example adapter block assembly include a first optical adapter; a first contact assembly disposed in an aperture defined in the first optical adapter; a first circuit board; and a retainer arrangement that holds the first circuit board to the first optical adapter with sufficient force to retain the first contact assembly within the aperture. Example retainer arrangements include a cover having flanges with tabs that deflect into cavities defined by the first optical adapter; clamp members that clamp a cover to the first optical adapter to hold the first circuit board therebetween; and a retention strip having barbs that attach to the first optical adapter and barbs that attach to the first printed circuit board.