L1T KVM 1.4 DP Issues - Mouse/Keyboard

Hello, I am new here and looking for any assistance that I can find on this.

I just got the L1T KVM 1.4 display port dual monitor delivered today. I was able to get the monitors to switch just fine between my PC and docked work laptop, but the two different mice (LG C903 and Razer Deathadder) light up when I plug them into the HID ports but do not respond. This is also the same with the keyboard (Durgod Taurus K320 TKL). Keyboard lights turn on but no actual keys work when plugged into HID, but does not work with USB 3 ports.

ive been waiting on usb cables, so initially i only had DP cables

Hooked up two PCs and my monitor to my KVM and i had green lights and could switch b/t PCs without issues (lights on front were green)

I remembered that i had some usb2.0 type a → b cables, dug them up and plugged them in. the lights on front went half green and red. couldnt switch b/t PCs.

ended up unplugging everything and power cycling kvm and only connecting one pc at a time… lights still half green/red but I can switch b/t the two PCs again.

I spent more time troubleshooting and reviewing what others that tried various means to get their HID and 3.0 ports to work, but all I can see is that both mice get power but no movement and the keyboard lights flash and then stop. So the ports are providing power, but not reading inputs. The green indicator light on the front does not turn on, meaning it’s not receiving input signal from any of the devices that are plugged in.

I had some issues with my HID ports on my new 1.4 KVM with 3/4 HID ports not working.

I was able to resolve them by unplugging the power from the unit followed by all the HID USB cables.

Then I plugged the power back in and then 1 HID device at a time and they all suddenly started working as expected.

I had tried that yesterday. Power cycling and seeing if it would work with nothing attached and slowly adding one in at a time. No green indicator light on either PC when I swap between.

i got mine working properly by unplugging the keyboard and mouse… power cycle, then plugging kb and mouse back in.

Can you take a picture of your cabling setup?

It sounds like you don’t have usb3 a to b cables from the host computers to the KVm?

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You are indeed correct. I do not have usb a to b cables. Problem solved.

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After a week or so I’m noticing an issue with Logitech G Hub getting hung up on either one of my systems when I switch back and forth. When trying to open the app, it shows that I have no G Devices connected (despite having a G502 Lightspeed, G Pro Wireless headset, and Logitech Brio webcam.

The issue goes away and G Hub responds as expected if I kill/restart LGHUB and LGHUB Agent process.

For clarification, my setup looks like this…

Hardware

  • L1T DP 1.4 KVM
  • Lenovo 480s Laptop connected to KVM via USB-C to displayport and USB3 cables.
  • Asus X570 based desktop connected to KVM via displayport and USB3 cables
  • Monitor: LG 34GP83A-B w/ USB hub connected to KVM USB 3.0 port on rear.

Peripherals

  • Logitech Brio Webcam connected to LG Monitor USB1
  • Logitech G Pro Wireless connected to LG Monitor USB2
  • Logitech PowerPlay/G502 Lightspeed Mouse combo connected to LT1 KVM HID Port on rear.
  • Logitech MX Keys Keyboard connected to LT1 KVM HID Port on front

Any ideas on what could be causing G Hub to hang all of a sudden?

Anyone else experiencing issues with G Hub?

try moving those devices from hid ports to a usb3 ports. the hid ports are meant for basic hid devices, so it might not behave with third party software the way you expect.

another wrinkle I sometimes see with logitech devices if you need the same driver loaded on all attached PCs. logitech is clever – the mx3 for example uses an 8 byte usb protocol until the driver is loaded. then it’s 20 bytes. so if one pc has a driver and one doesn’t when you switch and back it never comes back to the 20 byte protocol. stays at 8 bytes. the usb3 ports will try to leave the devices alone a bit more than the hid ports, though, so that’ll probably clear it up.

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