The Model BA-1 In-Line Isolator blocks audio while allowing power to flow to an isolated leg of the PL network.  The BA-1 allows one channel to support several simultaneous and independent conversations. The Main Station cannot communicate with the isolated legs of the network.  Private local conversations can occur along a common interconnect line without adding great lengths of cable or additional Main Stations. You may incorporate any number of BA-1's, as long as the power capacity of the Main Station is not exceeded by Remote Stations or Beltpacks.