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HDMI over CAT5 HDBaseT Extender - Power over Cable - Ultra HD 4K

Extend HDMI® up to 230ft (70m) over a single CAT5e/6 cable with Power over Cable to Receiver

Product ID: ST121HDBTE

  • Extend video where power outlets are limited with power over cable that powers both the transmitter and receiver using a single power source at either side of the connection
  • Maintains astonishing picture quality up to 115 ft. (35 m) away, with support for UltraHD 4K over non-proprietary CAT5e or CAT6 cabling
  • Also supports HD video resolutions such as 1920x1200 or 1080p at distances up to 230 ft. (70m)
View More
  • Hassle-free, professional installation with included mounting brackets, and full video extension over one CAT5 cable
  • 70m (230ft) maximum Cat5 cable distance
  • No software/drivers required
  • Mounting Hardware Included
  • Dolby® TrueHD, DTS-HD MA Audio
£260.99 GBP exc VAT
£313.19 GBP inc VAT
454+ In stock
Where To Buy
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Technical Specifications

Warranty Information
Warranty 2 Years
Audio Yes
AV Output HDMI
Cabling Cat 5e UTP or better
Daisy-Chain No
Ports 1
Audio Specifications 7.1 Surround Sound
Max Distance 70 m / 230 ft
Maximum Cable Length 70 m [229.6 ft]
Maximum Digital Resolutions 4096 x 2160 (4K) @ 30 Hz (35 meters)
1920 x 1080 (1080p) @ 60 Hz (70 meters)
MTBF 52,000 hrs.
Supported Resolutions 3840x2160 (4K)
1920x1080 (1080p)
1280x720 (720p)
Wide Screen Supported Yes
Connector A 1 - HDMI (19 pin) Latching Female
1 - RJ-45 Female
Connector B 1 - HDMI (19 pin) Female
1 - RJ-45 Female
Special Notes / Requirements
Note If you want to add more displays, you can daisy chain this product with the HDBaseT repeater ST121HDBTRP.
LED Indicators 1 - status LED (local)
1 - status LED (remote)
Center Tip Polarity Positive
Input Current 0.5A
Input Voltage 100 - 240 AC
Output Current 1.5A
Output Voltage 12V DC
Plug Type M
Power Consumption (In Watts) 3
Power Source AC Adapter Included
Humidity 0% - 80 % RH (non-condensing)
Operating Temperature 0°C to 40°C (32°F to 104°F)
Storage Temperature -10°C to 60°C (14°F to 140°F)
Physical Characteristics
Color Black
Material Aluminum
Product Height 2.5 cm [1 in]
Product Length 80 mm [3.1 in]
Product Width 67 mm [2.6 in]
Weight of Product 428 g [15.1 oz]
Packaging Information
Package Height 65 mm [2.6 in]
Package Length 15.6 cm [6.1 in]
Package Width 23.5 cm [9.3 in]
Shipping (Package) Weight 1.1 kg [2.4 lb]
What's in the Box
Included in Package 1 - HDMI over CAT5e/6 transmitter unit
1 - HDMI over CAT5e/6 receiver unit
1 - mounting bracket kit
1 - universal power adapter (NA/EU/UK/AU)
2 - grounding wires
1 - instruction manual


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HDMI over CAT5 HDBaseT Extender - Power over Cable - Ultra HD 4K

Customer Reviews

4 (8 reviews)
4 out of 5 stars
Quality of Product
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1 - 8 of 8 Reviews

(5 stars) Nice Picture

By: EdDyP123
I often like to show family members videos and pictures of our vacation and the kids from the computer on the TV. We also like to watch a lot of streamed content as well. My TV is not a smart TV so I can't stream content to it from my computer. I often have to copy everything to a USB stick and plug that into my TV. This eliminates that by being able to hook my computer from across the room to my TV as a monitor and watch media content on my TV from my computer without having to move it. Picture is clear without any degradation. The two units are small enough to tuck away out of sight. Did what I needed it to do. I received this product in exchange for an unbiased review.
Comment Helpful? Yes - 0 No - 0 Report

(4 stars) Great product with affordable price

By: djLuislatino
I got this adapter from Startech to test, and I'm using it now for about 2 months, and it is great. It responds very well and no freezing; it does the job, and I recommend it. Disclaimer : “I received this product in exchange for an unbiased review.”
Comment Helpful? Yes - 0 No - 0 Report

(5 stars) HDMI over Ethernet

By: Starr
We tested the device over 100’ of cable with great results. The picture quality appears to be flawless and the fact that it only requires power on one end is definitely plus. Highly recommended! The small converters on each end are easy to hide and it was a simple install.
Comment Helpful? Yes - 0 No - 0 Report

(5 stars) HDMI over network cable that works!

By: ScottG416
I was tasked with having users mirror their laptop on a tv (after the built was complete) without software and I have found the answer. A facility had just finished a renovation and the tv was mounted, power was installed and network drops were in place but no thought had gone into how to utilize the boardroom to its full potential. After much discussion with endusers and management the most cost effective way would be to use an HDMI extender without any software installation required (since most laptops are locked down these days). With cables plugged in (HDMI and CAT5/6) all is left for the user to do is to plug in HDMI to their laptop and we now have the laptop screen on the tv. Another great product from I received this product in exchange for an unbiased review.
Comment Helpful? Yes - 0 No - 0 Report

(4 stars) Very solid product for the AV professional

By: NickD
I have been using this product for a few weeks now to send HDMI signal over Ethernet and so far so good. I have used this with several devices and TVs/projectors with no problems. (Computer, Laptop, Tablet, Xbox 360, Xbox One S, Android boxes, Nintendo Classic, 1080p TV, 4k TV, 720p Projector, through surround sound Receivers, etc.) This package comes with everything except the HDMI cables (mounting brackets, grounding wires, screws, short Ethernet cable, power connectors with ends for different countries, etc.). The instructions provided are very simple and don’t offer much information other than the basics. For example, grounding wires were provided but it's not clear which applications they would be required for. This product worked well without the grounding wires connected. I suppose I would connect the grounding wires in a more demanding environment with a permanent installation. For now I like that they can easily be moved. The mounting brackets are universal and can be setup in several different ways allowing very flexible installation of the boxes. I like that you can apply power to either the receiver or the transmitter and it will power both ends (only one power supply is needed). The devices are made very solid with metal. They were shockingly heavy and seem very durable. I suspect these will be able to survive quite a few drops and bumps. After about 20 minutes of use, both the receiver and transmitter got very hot. I was nervous that I would not be able to touch them soon. After a few more hours of use they remained "very hot" but I could still pick them up and hold them if needed. The temperature worries me so I will keep and eye on them. My only wish is that it have an IR return option like similar products so the source device could be controlled from the receiver. The lack of IR return and the worrisome heat this device make are why I gave this a Good rating instead of Excellent rating. So far I am happy with this product and will continue to use it often. I received this product in exchange for an unbiased review.
Comment Helpful? Yes - 6 No - 0 Report

(4 stars) HDMI Over Cat 5e/6 Made Easy

By: James H
I have been in the technology business for over 35 years and for the past 20+ years I have been asked to provide unbiased reviews of various products from both the AV and IT world. In review of this product I have found that it works up to 1920x1080 resolution which is common for TV viewing in 16:9 format, with the accompanying audio The ease of use was well thought through, simply plug in the source and display and connect over Cat5e and the unit does the rest. When testing this unit at 4K Resolution 3840 × 2160 or UHDTV, I noticed a very slight bit of pixelation during fast motion, that distance was at 100'. My only negative would be that I could not get this product to perform ARC (Audio Return Channel), so I it will not be a solution for a Smart Hub/ Audio Return sound. In the box: -HDMI over Cat5e/6 Transmitter -HDMI over Cat5e/6 Receiver -Universal Power Adapter (NA/UK/EU) Mounting Bracket Kit Cat5e Cable -Instruction Manual In summation, solid product, easy to install, set up and use. I received this product in exchange for an unbiased review.
Comment Helpful? Yes - 0 No - 0 Report

(4 stars) Great build quality, not the best instructions

By: Macphoto1970
So tested this unit and first thing I will say is the construction quality is great. Parts seem to be of excellent quality. Nice that the power adapter has multiple heads for different countries and power supplies. The brackets included are of excellent quality. Now trying to set this up was a bit of a challenge for someone who has never attempted. I was testing over a 50ft cat 5e cable, from my windows pc running windows 10 to a samsung smart tv one floor up. Now the setup appears easy. Connect the receiver connect the transmitter, cable in the middle and go...well not so easy...I found I would get a red light on one of the receivers and blue light on the other. The instructions are not clear really at what to do or what this means so by trial and error I tested. I switched the source (the computer) to a blu-ray and used the supplied cat5 cable and voila it worked. great picture etc. Now I did some research and maybe it was an issue with my cat 5e cable. they provide some green grounding wires but the instructions do not make it clear as to what we are to do with them. and the instructions talk about grounded cat5e cables etc. As a novice with this..I am not sure if that is my whole issue. Do I use these grounding cables into a power outlet? still not sure. The item itself does work and does display and excellent picture. Once my cabling issue was solved all seemed to work very well. I am impress with the quality of the picture and I like the fact that only one power cord is needed as I find too many items need power behind my tv and this made for one less power cord! Overall it is an excellent product just a few more troubleshooting tips in the user manual and on would be helpful “I received this product in exchange for an unbiased review.”
Comment Helpful? Yes - 0 No - 0 Report

(1 star) Does not work on my redeliver

By: EnIXmA
Bought this specifically for my 4k TV which is being connected by the latest onkyo receiver... Connected, and everything perfectly fine for 2 days... For some reason it just shows no signal on my TV now... The lights are blue so the connection should work, but it doesn't. Seems like I wasted 300 bucks on this and got no way to run my ht system
Quality of Product (1/5)
Comment Helpful? Yes - 1 No - 7 Report
Response from
Barry, Customer Support
Hello, Thanks for sharing this feedback with us. It sounds like HDMI "handshake" between the connected devices is corrupted. The following steps will outline the EDID reset procedure for the ST121HDBTE and should be off assistance for you, or any others experience this issue. 1. Power down the Onkyo box (or other device) and TV, unplug the power cables, then unplug the extender. Disconnect all HDMI cables temporarily. 2. Wait 30 seconds with all devices disconnected. 3. Re-connect the power to the extender. 4. Re-connect the TVs and Onkyo box (or other). 5. Power the TVs back on. 6. Power the Onkyo (or other) receiver back on. As always, if this does not correct the issue, please contact our Technical Advisors by clicking the "Support" link at the top of our website. Thank You.