The SF-MA100A is an audio power amplifier that receives three audio channels on an RJ45 Format-A connector. The three inputs are mixed either by the three rear-panel potentiometers or remotely by the three potentiometers on the remote control (available separately). Local or remote control is defined by the Mode switch on the rear panel. If the mixer is remote-controlled, the rear-panel potentiometers set the maximum gain applied to each input.