The D SERIES-J1 is a complete microphone input panel assembly. Connections to the female front‑panel XLR jack are made on a rear barrier block. Four terminals are provided: CASE GROUND, SHIELD (XLR pin 1), + (XLR pin 2) and - (XLR pin 3). The installer may install a jumper between the SHIELD connection and CASE GROUND if desired. The back of the D SERIES-J1 is finished with a metal enclosure clearly labeled for easy installation.The D SERIES-J1 fits directly into back boxes, available from RDL to fit cabinets or US or international walls (RDL WB-1U). They may be mounted directly into cabinets or most standard US single gang electrical boxes.