A socket assembly has a housing holds a circuit board that is provided with contacts for engagement with a data plug and a back face provided with rearwardly projecting blade contacts. A conductor spreader block engageable in a rear housing end fits with conductors of a multiconductor cable and, when fitted in the housing, electrically engages the conductors with the blade contacts, A holder in the base between the spreader block and the board has an open back side through which the block can fit. The holder forms a first U-shaped half seat, and a cover subassembly forms a second U-shaped half seat and is pivotal on the holder between an open position projecting laterally therefrom with the cable passing loosely into the housing and a closed position rearwardly closing the holder and compressing the cable between the half seats and locking the block in the holder.