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Connect the DB37 cables provided with the Opal-RT simulator to the back connectors on the OP8210 Interface Connector.
Connect the external device to the desired channel connectors on the front of the Interface Connector.
Depending on the type of board used in the simulator, the OP8210 connector may require an external power supply (example: when using a digital output board).
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For more information about the use of Vuser and Vrtn pleaser refer to this article in the OPAL-RT knowledge base : How to power the different DB37 boards for digital outputs.