The SCS 1 serial connection board is for the QSC D MA, LIBRA C MA, LIBRA C MV, LIBRA C LX, VENERE D, LEO D MA, LEO MV, RIGEL 5 and ALTAIR P. Connecting two BFT gate operators to work together as a master/slave on the same transmitter requires the installation of a serial connection board on both operators and then connecting them with a 18-20 gauge wire.