Color vision for network techs

Hello, Do any of you do any color vision screening in your interview process? How do those of you with color vision impairments compensate? I'd never considered this until I was in one of our facilities with my son (who has limited color vision) and we had a discussion about the LEDs. He could only determine on/off - not amber/red/green on the equipment we had. I'm wondering if we need a color vision requirement (or test) as part of our hiring requirements. Berry Mobley