I have a problem with a HDMI/USB extender ST121USBHD

Hi. I am trying to get a HDMI extender to work but I am not getting any video signal.

Source: Lenovo Thinkcentre HDMI running Windows 11 Pro

Connected the local unit to the computer with a StarTech.com HDMI cable

Connected the local unit to the remote unit with the included RJ45 patch cable

Connected the remote unit to my local monitor with a StarTech.com HDMI cable

Windows detects the monitor as “phl bdm4350”. This is not correct as I have a LG monitor.

My monitor acts like its waking up when connecting the extender but no signal is detected.

I have checked the resolution in windows and it is set to 1080p 60hz.

I have no clue to what’s causing the problem and I’m hoping some of you can help me.

Thanks!

Hello Roger and thank you for your interest in our Community.

For dedicated video extenders such as our ST121USBHD, you’ll want to make sure that you are using both Ethernet cables between the LOCAL and REMOTE end. Please also verify that each end correctly connects to the equivalent port on the other end (VIDEO to VIDEO and AUX to AUX) and make sure to use cables of the same length (15m for CAT5e, 30m for unshielded CAT6 and up to 40m for shielded CAT6). The connection must be point-to-point (single Ethernet cable) and cannot go through a network equipment such as a network hub, switch, router or etc.

If this does not work, I would invite you to try different HDMI source and HDMI displays as well as taking note of the LED status lights on the unit, this should give us a better idea of where the issue may be at.

I hope this helps! If you are still unable to get it working, please feel free to reply and I’ll be happy to assist you further.

Emmanuel B.

Hello, we have an issue with the StarTech ST121USBHD switch: for some customers the keyboard stops working after a while (the monitor works correctly). To get it working again, simply unplug and reconnect the keyboard’s USB connector, and it works again for a period of time. The operating system is Windows 10 32-bit. We would like guidance on how to resolve the problem. Thank you.

Hello @Vadim,

I am sorry to hear about the trouble you are having with ST121USBHD.

If the keyboard being used through the extender is a wireless keyboard or one that has additional features, such as LEDs or additional keys, I would recommend to test a basic wired keyboard. Sometimes non standard keyboards such as these can experience issues when working through an extender.

Can I ask if the computer that is being used is actively being used when the keyboard loses connection or if it has been idling for some time? If it has been idling, it could be possible that the USB port on the computer is going to sleep to save power due to inactivity and using the keyboard does not wake it but the signal from disconnecting and reconnecting it is enough to wake the port back up.

I would also suggest reaching out to our team support team directly using the options at https://www.startech.com/support. Live interactions through phone or live chat can often have a quicker turnaround to a resolution and then we can update the community post with the resolution.

We look forward to hearing back from you.

Lukas T

1 Like

Hello Lukas ,

The customer is far away from us and we encountered this issue, we advised him to connect a second power supply to the receiver so that both modules are powered.

Unfortunately, the customer misunderstood and moved the power supply onto the receiver, so only the receiver is powered for now.The keyboard is a basic wired model with no backlighting.

The USB port should be set to default as not in standby. I will check this setting as soon as the customer provides remote access to the PC.

We are waiting for any updates and I will let you know as soon as we have further developments.