Soundtronics Wireless has taken the standard HME 800 system one step farther. By incorporating a technology know as TLO, (Transmitter Lock Out), we have increased the number of user from four to six, eight, and even 21 Beltpacks pre base station. This system still utilizes the 4 independent listen-receive controls of the original unit, but adds the TLO to the forth beltpack frequency allowing multiple user on that frequency. Each of the additional stations have the same Main/ISO Talk-Listen capability, with the TLO circuit only allowing one user to talk at at time.