Isolating switching amplifier, 4-channel, operating voltage 20,250 VAC / 20,125 VDC, five transistor outputs, short-circuit proof, potential-free and reverse polarity protected, adjustable direction of action (working/quiescent current behavior), monitoring of the input circuits for wire breakage and short circuit (can be switched on/off), general fault signal output, all-round galvanic isolation, input reverse polarity protected, ATEX, IECEx, UL, CFMUS, CSA, TR CU,INMETRO, TIIS, Nepsi, use in zone 2