The For.A Interface Serial Port Option Adds Genlock Input, Color Selectable (Red And Green) Tally Indicator (IF-SP-G-TL) is a professional-grade device that can be used to add genlock input and color selectable (red and green) tally indicator to For.A HVS-490HS, HVS-500HS, HVS-1000HS, HVS-1500HS, HVS-2000HS, and HVS-3000HS video switchers.