XJExtender is XJTAG’s recommended solution to overcome signal integrity issues when connecting an XJLink2 JTAG controller to a remote Device Under Test (DUT). By using differential signalling, XJExtender allows you to work with a DUT up to 10 meters from the XJLink, even in electrically noisy environments.

Product sheet Technical Specifications User Guide STEP model Contact us

Key Benefits

  • Reliably extends the distance between XJLink2 Controller and DUT
  • Allows DUT testing in larger installations or environmental chambers
  • Provides superior EMI immunity to preserve signal integrity
  • Improves the overall performance of test systems
  • Can be used with other XJTAG hardware including XJIsolator and XJXDP


  • Standard 26-way IDC connectors support cost-effective ribbon cable for board-to-board connection (twisted-pair ribbon cable recommended for best performance)
  • TCK clock frequencies up to 50 MHz
  • Flexible power supply voltage: 5 V to 15 V (2 required, not included)
  • Variable I/O voltage from 1.8 V to 3.3 V (when used with XJLink2)
  • Provides 8 channels configurable as uplink or downlink (default configuration: 6 downlink/2 uplink)
  • Controller unit plugs directly into XJLink2 though standard 20-way IDC interface
  • Target unit connects directly to DUT using standard 20-way IDC socket

Extending performance

Poor signal integrity between an XJLink controller and DUT may force you to reduce TCK frequencies, or even stop you running tests.

The high levels of electrical noise that often exist in test environments can cause signal integrity problems when running JTAG tests; problems that can be made worse if a DUT has to be placed away from the XJLink, in a fixture or an environmental chamber.

XJExtender overcomes these issues by supporting cables up to 10 metres long without compromising signal integrity.

XJExtender controller target units & XJLink2

Flexible configuration

XJExtender comprises a Controller unit connected directly to an XJLink controller, and a Target unit connected to the DUT. Target units can be purchased separately to supports workflows that require Target units to be permanently located within test fixtures.

Each unit offers 8 channels with a default configuration of 6 downlink (Controller to Target) and 2 uplink (Target to Controller). This can be reconfigured using on-board solder links to any combination of uplink/downlink channels.

Extending signal integrity

Using the Low Voltage Differential Signaling (LVDS) standard as the physical layer between the Controller and Target, XJExtender allows high speed communications over flat or twisted-pair ribbon cables.

As each channel uses differential signalling, the cable generates low levels of Electromagnetic Radiation (EMR); important when testing sensitive electronic assemblies. It also exhibits very high immunity to Electromagnetic Interference (EMI), which enables the use of longer cables without loss of signal integrity.

Extended temperature range

The XJExtender units support an extended temperature range of -40 °C to +85 °C. This makes XJExtender the ideal solution for testing a DUT in an environmental chamber.

Please contact your local distributor for a quote.

Ready to get started? Try XJTAG


See XJTAG in action.

Our experts will be happy to show you how the XJTAG tools can help you diagnose faults on your board as well as cutting test development and repair time.

Ask for a Demo

contact us icon

Questions? Contact us!

We're here to help.
Send us a message and one of our test specialists will get back to you shortly.

Contact us


Get a free test setup.

Evaluate the XJTAG system with full functionality for 30 days and get the first test project set up for your board – for free. No obligation to purchase.

Get started now

Join world leading companies using XJTAG Boundary Scan