KVM Model:
1.4 Display Port KVM Switch - Dual Monitor - Four Computer
USB Interface (5-gigabit or 10-gigbit):
*10-gig
Problem:
As I troubleshoot I am accumulating problems.
Initially it started as the scrren being recognized by windows, but the hardware not turning on. I have doen the following without success:
- Swtich screen (they were of different brand)
- Get a two screen from the same model
- Switch laptop (I use a Dell dock)
- Bypass the KVM switch
- This is the only one that works. Both screen works well, which lead me to say the Dell Dock isn’t contributing to this problem.
What was interesting, is that if I swapped the DP cables in the “Console” section, the other screen the screen working would stop working and the other one would start correctly.
I decided to unplugged the KVM and hope it would reset itself. However, since I did that, the console HID are no longer working (keyboard and mouse). They used to work.
I am a bit loss now. I don’t know what else I could try.
Other Notes:
type here
can you post a pic of how you have it cabled?
unplug the oven from power and USB and all cables and try to connect power to the kvm only and confirm the front button still works to operate the kvm.
the hid ports are meant for driverless peripherals and that may be another variable we can deal with separately.
Hello, I am not sure if I am answering your questions but here is my best shot. Welp, I am apparently limited in the number of pictures I can upload.
Only power plugged in KVM, nothing else
Lights turn on, all 4 button will switch.
plugging DP cables:
Topology (If you want a picture with all cables and connection, that will take me a bit more effort to set up).
Laptop → USB DELL DOCK → FIBR DP → KVM → 3DCLUB DP → Screen
The screen is recognized by the OS (which to me indicates the electrical connection are working). If I turn off the screen it will disappear from the configuration menu.
Peripherals
I tested them directly connected on my computer and they still work. I plugged them in again hoping it would work but nothing.
those are the fibbe brand copper cables right, not fiber optic? the counterintuitive thing here is that the losses of cables through the kvm are additive. so one cable in plus one cable out losses are just below the threshold to decode signal. that’s why you don’t get signal but the laptop detected the display I suspect.
is the total length of dp cables here under 10 feet? it can be longer of those are truly fiber optic cables
club3d is a recommended brand for copper cables. a 3 foot and a 6 foot for copper is okay probably.
from the gpus point of view it sees the kvm and both cables on either side of it like it’s one long signal corridor. since it works with one but not the other the one probably will cut out from time to time because the signal overall is marginal.
also, which model dell dock is this? they have a firmware update that you might need.
those are the fibbe brand copper cables right, not fiber optic? the counterintuitive thing here is that the losses of cables through the kvm are additive. so one cable in plus one cable out losses are just below the threshold to decode signal. that’s why you don’t get signal but the laptop detected the display I suspect.
Yeah, I remember being surprised that FIBBR sold copper cable. I believe I bought fiber optics ones. Both cable have a sticker identifying them. (pictures attached)
F-dp21-8k-3: I belive the first letter confirms it is fibber optics
CAC-2067
topology (same for both screen)
Screen → Copper Club (3ft) → KVM → FIBBR Optic (3ft) → Dock
is the total length of dp cables here under 10 feet? it can be longer of those are truly fiber optic cables
6 ft total, but there is a transmission medium change in the chain.
Forgot to add the pictures…
The model is a Dell WS19S. I just ran firware update on it. I have the same behaviour, screen detected by the OS, but not transmitting.
If I connect the screen directly to the dock (bypassing the KVM) both screen operate at 4k.
now the dock firmware is updated can you try unplugging the kvm dock and monitors from power for a few mins? if possible use the two 3 foot copper club3d cables to check one side of the kvm at a time so when you’re powering it back up we can make sure both sides of the oven work with the copper cables.
the fiber cables are also directional in case that matters. i.e. source end and display end are not the same
Gotta say, I never had a forum thread that responsive. I really appreciate this.
if possible use the two 3 foot copper club3d cables to check one side of the kvm at a time so when you’re powering it back up we can make sure both sides of the oven work with the copper cables.
Test results
Conditions:
- One screen plugged at the time. Only with 3DClub Copper cable.
| Cases |
Console DP Port |
PC4 - DP Port |
Dock |
Screen |
Screen is detected by OS |
Screen is active |
| A |
top |
top |
R |
1 |
Yes |
Yes |
| B |
top |
top |
R |
2 |
Yes |
Yes |
| C |
bottom |
bottom |
R |
1 |
Yes |
Yes |
| D |
bottom |
bottom |
R |
2 |
Yes |
Yes |
| E |
top |
top |
L |
1 |
Yes |
Yes |
| F |
top |
top |
L |
2 |
Yes |
Yes |
| G |
bottom |
bottom |
L |
1 |
Yes |
Yes |
| H |
bottom |
bottom |
L |
2 |
Yes |
Yes |
I went ahead and connected the whole thing using copper cable only and both screen are displaying correctly!
So right now the main suspect is the FIBBR cable!
the fiber cables are also directional in case that matters. i.e. source end and display end are not the same
Let’s see if that was a factor…
Switched the two PC4 DP cable for the FIBBR one. And I have two screens displaying and being recognized. It is awesome.
Root cause: user didn’t read the cable connector correctly and plugged the display connector in the source port.
So one problem solved, I’ll try the HID again
The mouse and keyboard are still not working, regardless of the HID port being used 
so what keyboard and mouse are they specifically? remember hid is meant to be driverless.
in all the pics youve shown so far the USBC ports haven’t been connected to anything. those connect back to the host PCs.
I don’t know what to say. This has been brain farts after another.
Indeed if you plug the US from PC4 to the dock, all works well. Obviously.
All the issues are resolved now.
1 Like
And I should say:
Thank you for being so responsive over the weekend. You really stand behind your product in a way never seen before!
no worries. fibbr is usually insanely reliable so glad you posted as it seems like you might have a dud cable. it’s weird the way the kvm works where you can have a marginal cable that works ok by itself but not in a mix. the kvm doesn’t repeat the signal in a way that messes with subtiming but that also means the cables have to follow vesa spec for exactly this situation with a kvm or passive cable extender
anyway it’s good telemetry for us to know what cables periperhaps work and what’s ornery
