Why are my keyboard and mouse not working on my KVM switch?

This article was created from a community discussion by @MattS

The USB ports on a KVM switch act like a USB hub. Therefore, KVM switches require both a video cable and a USB cable to connect to each computer to allow both the video and the USB ports to function properly. In most cases, a USB-A to USB-B cable, such as StarTech.com’s USB2AA2M can be used for the data connection, though some KVM switches only have a VGA port on the KVM side may require a proprietary KVM cable such as the SVECONUS6.

This FAQ applies to these products: DP4N1USB6 DVID4N1USB10 DVID4N1USB15 DVID4N1USB6 PS23N1THIN15 PS23N1THIN6 SV1108IPEXT SV1108IPPOW SV1115IPEXT SV125 SV1631DUSB SV1631DUSBU SV1631DUSBUK SV1641HDIE SV1653DXI SV211DPUA SV211HDUA SV211KDVI SV211KUSB SV211USB SV215MICDVIA SV215MICUSBA SV231 SV231DD2DUA SV231DDUSB SV231DDVDUA SV231DLU3A SV231DPDDUA SV231DPDDUA2 SV231DPU SV231DPU2 SV231DPU34K SV231DPUA SV231DVGAU2A SV231DVIDDU SV231DVIUA SV231DVIUAHR SV231DVIUDDM SV231HDMIUA SV231MDPU2 SV231QDVIUA SV231TDVIUA SV231U3A SV231UADVI SV231USB SV231USBA SV231USBDDM SV411K SV411KUSB SV431DD2DUA SV431DDUSB SV431DDVDUA SV431DHD4KU SV431DPDDUA2 SV431DPU3A2 SV431DPUA SV431DPUA2 SV431DUSB SV431DUSBU SV431DVGAU2A SV431DVIDDU SV431DVIUA SV431DVIUAHR SV431DVIUAQV SV431DVIUDDM SV431HDU3A2 SV431TDVIUA SV431U3A SV431USB SV431USBAE SV431USBDDM SV441DUSBI SV5USBM SV831DUSB SV831DUSBAU SV831DUSBU SV831DUSBUK SV831DVIU SV841DUSBI SV841HDIE SVECON10 SVECON25 SVECON50 SVECON6 SVECONUS10 SVECONUS15 SVECONUS6 SVPS23N1_10 SVPS23N1_15 SVPS23N1_25 SVPS23N1_50 SVPS23N1_6 SVUSB2N1_10 SVUSB2N1_15 SVUSB2N1_6 SVUSBVGA10 SVUSBVGA6 USBDVI4N1A10 USBDVI4N1A15 USBDVI4N1A6 USBVGA4N1A10 USBVGA4N1A6 SV231HU34K6 SV231QDPU34K