JTAG TapCommunicator facilitates remote execution and diagnostics of boundary-scan applications, regardless of distance or environmental difficulties. The off-the-shelf system is based on a one gigabit ethernet connection (IEEE Std 802.3z) providing virtually unlimited range between the controller and target. TapCommunicator is based on the ‘licencable’  TapSpacer IP, technology that allows any (packetised) communication link to be used. For solutions using communication links other than Ethernet, contact JTAG Technologies.

The standard TapCommunicator system consists of an “uplink” or primary module (JT 2143), located in proximity to the boundary-scan controller, and one or more “downlink” or secondary (JT 2144) modules at the target. Licenced TapSpacer systems will work in a similar way though it is expected the compact logic code (for uplink and downlink) will be integrated into the users own ASIC or FPGA.


  • Encodes and decodes JTAG for long distance transmission
  • Based on TAPSpacer IP/technology
  • Standard unit is gigabit ethernet based
  • Supports use of the existing Ethernet communication channel to a system for remote operation of boundary-scan
  • Allows unlimited distance between target and boundary-scan controller without need for range extenders
  • Overcomes harsh environments and other situations where human access to the target would not otherwise be possible
  • Enables sharing of a single boundary-scan controller or a pool of controllers among multiple production platforms
  • Overcomes range limitations of adaptive clocking techniques
  • Supports all brands of boundary-scan controllers

All applications that require access to the boundary-scan chains without physical proximity (eg. application execution where human access is not possible) can be supported by TapSpacer technology. Examples of the range of new applications made possible by the Ethernet-based TapCommunicator are:

  • Remote system control
  • Environmental testing
  • Factory with multiple production lines
  • Contract manufacturer with different brands of boundary-scan controllers
  • Supports remote boundary-scan operation
  • Gigabit Ethernet channel between controller and target
  • Zero signal degradation between uplink and downlink modules
  • Full boundary-scan IEEE std 1149.x functionality

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