The IT-R4 is a multi-purpose switch or logic level activated Relay Module. Four user configured relays are controlled via five input ports that are designed to accept either a switch contact closure or logic level input. A four-position configuration dip switch sets the operating behavior of the relays. Each relay can be set for different operating modes; "On, "Off", pulsed for a ? of a second, or toggled, which changes the relay to the opposite state.  Power Requirements: Power Supplies are sold separately. One Power Supply can power up to (6) IT-R4 and/or IT-R4S modules, saving wiring headaches and money.