Why does my Startech SV231 USB KVM Only work with some devices

Question

I have a StarTech SV231 USB 2-Port KVM switch. I can't get it to connect and work with two different computers...

I have three computers I have tested it with and it only works with 1 of them. (Yes the KVM is plugged in and powered...)

• Working Computer - (Custom Build) ASUS M5 A97 LE R2.0 MOBO
• Non Working Computer - Dell Latitude E7440 (Have tested on and off Docking Station, USB ports work fine when Keyboard and Mouse plugged directly into them, have tried all ports). I have tested having the KVM switched to this computer and doing a cold boot, still doesnt work. I have enabled "Wake from USB" in the BIOS, this was the only relevant BIOS option I could find.
• Non Working Computer - (Custom Build) ASUS P5N-E SLI MOBO - same as above, have tried all USB ports and a cold boot.

I don't understand how / why this will not work, I have a un-powered USB hub which works with all three computers and the two peripherals connected. The keyboard is a DELL KB212-B and Mouse is a classic Microsoft White 5 Button Optical USB InteliMouse.

The USB portion of a KVM should be a hub and the parent USB connection gets disconnected and reconnected to the other parent USB port when the switch is pressed?

The StarTech manual says to change the following BIOS options, which do not exist in a DELL BIOS :

1. In STANDARD CMOS, set HALT ON ERROR to ALL BUT KEYBOARD
2. In PNP and PCI SETUP, set PNP OS INSTALLED to YES and set USB IRQ to ENABLED N

I don't think its a problem Mouse / Keyboard as they are both quite standard devices, which work fine through a Hub connected to any machine and also through the KVM Switch whilst connected to Computer 1.

Any help or advice people might have is very welcome - over the years I have had many problems with different KVM's and can never understand why, when simple unpowered USB hubs work fine.

Answer 1

I had been using many OEM version of Startech SV231. They are all the same - an USB Hub-based KVM switch. USB Hub-based KVM switches most likely are the cheapest KVM switches you can find in the marketplace. However, in team of the sharing devices' transparence to the KVM's connected systems, the Hub-based KVM switches are the best in device transparence - it is just like physically plug your devices and unplug your devices when switching amount KVM ports.

Because the nature of the HUB-based KVM switch, so most of KVM issues related to it (as you stated with your case) are system's USB ports/ USB setup issue or USB power issues. I suggest to plug in the USB cable between your system and the KVM switch to different USB ports on your system and to see if any different results. For example, we suggest plug in your USB cable to the rear panel of your systems.