Only for studio interfaces DO 12, DDO 120 or another relay card :
Allows you to cause the activation of relays and check if the external action who is suppose to happen is correct.
Example : To activate the 1st relay, tick "Relay 1", then click on "ON". Relay 1 changes of status; To undo, click on "OFF".
It is also possible to select "All" to activate with 1 click all the relays.