We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Compact HDMI extender kit with USB-powered transmitter and rack-mountable receiver

STARTECH

STARTECH ST121HDBTDK 4K HDMI Extender 70m HDBaseT v extender

SKU CH-Q3GR-VK5W3 MPN ST121HDBTDK

Extend 4K HDMI up to 70 m or 1080p up to 230 m over a single CAT5e cable with a USB-powered transmitter and 7.1 audio support

  • SpecificationHardware Audio: Yes Cabling: Cat 5e UTP or better Daisy-Chai
  • FeatureExtend HDMI video over CAT5 or CAT6 cabling up to 230 feet a
  • Dimensions0.98" x 2.68" x 3.15"
  • Weight8.89 oz.
  • Package Content1 x HDBaseT transmitter 1 x HDBaseT receiver 1 x USB power c
  • Compact USB-powered transmitter simplifies discreet installation
  • Extends 4K UHD video up to 70 m over single Cat 5e cable
  • Maintains 4K quality at 40 m distance
  • Supports 7.1 surround sound for full audio fidelity
  • Includes mounting hardware for professional receiver setup

Compact 4K HDMI Extender Kit

This HDBaseT extender transmits HDMI video and 7.1 audio up to 70 m over a single Cat 5e or better cable. The transmitter draws power from a USB port on the source device and includes a built-in HDMI cable for a compact footprint. Mounting hardware for the receiver is supplied for a professional installation. Ideal for digital signage and remote display applications.

Suited for integrators needing long-distance 4K

The kit delivers UHD 4K at 40 m and 1080p at the full 70 m range, making it a fit for displays within those limits. It is not for buyers who require daisy-chaining multiple receivers or transmitting beyond 70 m. The single-cable design also means it cannot support installations that demand dual-cable redundancy.

HDBaseT range defines the use-case

At 40 m the extender maintains 4K UHD resolution, while 1080p and lower resolutions reach the full 70 m distance. This single specification determines whether the link length matches the required image quality.

Highlights

  • Compact USB-powered transmitter simplifies discreet installation
  • Extends 4K UHD video up to 70 m over single Cat 5e cable
  • Maintains 4K quality at 40 m distance
  • Supports 7.1 surround sound for full audio fidelity
  • Includes mounting hardware for professional receiver setup

Specifications

BrandStarTech.com
ModelST121HDBTDK
SpecificationHardware
Audio: Yes
Cabling: Cat 5e UTP or better
Daisy-Chain: No
Output Signal: HDMI
Ports: 1
Rack-Mountable: Yes
Performance
Audio Specifications: 7.1 Surround Sound
Max Distance: 70 m / 230 ft
Maximum Cable Length: 0.2 ft [0.1 m]
Maximum Digital Resolutions: 4096 x 2160 (4K) @ 30 Hz
Wide Screen Supported: Yes
Connector(s)
Connector A:
- 1 x HDMI (19 pin) Female Input
- 1 x RJ-45 Female Output
Connector B:
- 1 x HDMI (19 pin) Female Output
- 1 x RJ-45 Female Input
Local Unit Connectors:
- 1 x HDMI (19 pin) Latching Female Input
- 1 x RJ-45 Female Output
Remote Unit Connectors:
- 1
FeatureExtend HDMI video over CAT5 or CAT6 cabling up to 230 feet away, with a small USB-powered transmitter for discreet installation
Works with HDMI video sources such as Blu-ray players & computers and HDMI televisions monitors and projectors
HDBaseT Extender / HDMI over single CAT 5 or CAT 6 Ethernet Extender / HDMI Extender Over CAT5 or CAT6 / HDBaseT CAT5
4K resolutions at 130 ft. away
1080p resolutions at 230 ft. away
Easy and discreet setup with a compact transmitter that's USB powered
Dimensions0.98" x 2.68" x 3.15"
Weight8.89 oz.
Package Content1 x HDBaseT transmitter
1 x HDBaseT receiver
1 x USB power cable (transmitter) (1310mm)
1 x universal power adapter (receiver) (NA / EU / UK / AU)
1 x mounting kit (receiver)
1 x screw kit for mounting
1 x footpad set (receiver)
1 x quick start guide
Shipping weight1.13 kg
Package size254 × 203 × 152 mm

Questions about this item

Does the kit include both transmitter and receiver, or do I need to buy a cable separately?

The box contains one HDBaseT transmitter with a built-in HDMI cable, one receiver, a USB power cable for the transmitter, a universal power adapter for the receiver, mounting hardware and footpads. A Cat 5e UTP or better cable up to 70 m is required and sold separately.

When should I choose the 70 m reach versus the shorter 40 m figure?

The extender delivers 4K UHD resolution up to 40 m (130 ft). For 1080p or lower resolutions the signal reaches the full 70 m (230 ft) distance. Select based on the resolution you need at the far end.

What does the 4K claim mean when the unit is installed in a real setup?

At distances up to 40 m over a single Cat 5e or Cat 6 cable the extender passes UHD 4K video with 7.1 surround sound. Beyond 40 m it falls back to 1080p while still reaching 70 m.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.