CLASSIC,10WATT W/MOH INPUT C10(MOH) & C20(MOH) have 10W and 20W output power respectively,Transformer isolated 4W,8W,16W,25V and 70V output taps, Rear-panel auxiliary receptacle, One dedicated Mic1 inpjut ù Lo-Z balanced, One switchable Mic2/Aux1 input, Contact activation of Aux input, Transformer-isolated 600W telephone paging input, Rear-panel-mounted TEL volume control, Voice activated muting of Aux input by Tel input, Variable trigger threshold for voice activation, MOH models provide 1W @ 8W and 1V @ 600W outputs of Aux input (only for telephone music-on-hold inputs), Optional wall mount kit, Optional impedance matching transformer 10K/600W