Model 9093 Dual Channel DB9 A/B/C Switch allows sharing of one DB9 device among 3 others for both channels and eliminates need to plug and unplug cables. High-quality sealed unit lets users simultaneously switch two DB9 channels via front panel rotary switch. It features self-wiping metal contacts encased in anodized black box with EMI/RFI shielding. No external power is required.