Attaching Ring 2 to existing intercom system

Looking for help here! I bought my parents a Ring 2 doorbell that we are finally getting around to installing. Their existing doorbell was connected with two wires. One red one black. There are two wire not connected that are orange and yellow. They have the old 80’s intercom console that the doorbell rings thru. Connecting with the black and red wires don’t power the ring doorbell. I tried connecting using the orange and yellow wires and successfully got power. The problem is that the when we ring the bell, the inside chime never goes off. It rings continuously. What are we doing wrong?