Supporting multi-drop operation, IA-3128S-U2i features 24 relays rated at 5 A @ 30 Vdc and 250 Vac. Solely wired, 24 isolated digital inputs are rated at voltage isolation of 2,500 V RMS and operation current starting at 2 mA. USB port is Isolated from host computer to avoid EMI/RFI factory floor noise, and relay contacts are protected by on-board voltage suppressors. Of 24 digital inputs, two may be used as Event Counting inputs. All digital inputs include programmable digital filter.