DPA-400 and its AUX Channel Monitor user interface (GUIprovides a compact, pocket-sized tool for recording and analyzing DisplayPort AUX channel traffic. It enables the user to monitor, capture, and document all AUX Channel transactions over a DisplayPort link.  

AUX Channel Monitor GUI detects, timestamps, and parses all DisplayPort Configuration Data (DPCD) reads and writes, Multistream (MST) Sideband Channel Communication, and EDID reads. 

The GUI is able to parse DPCD registers for DP versions up to 2.1. It decodes HDCP 1.3 and 2.3 messages and DP Sideband Channel Communication messages.  

The activity of the Hot Plug Detect (HPD) signal and optional user-defined input signals will also be tracked and time-stamped. 



Raw and Parsed Message Data

DPA-400 GUI parses all data captured from the AUX Channel traffic. This makes it straightforward for the engineer to follow the Sink / Source communication, the CTS test execution, and refer it to the requirement of the standard. AUX Channel Monitor GUI lists every AUX Channel event and DPCD content both as time-stamped raw data and in a parsed form. The details are explained with the same terminology used by the relevant VESA standard and the Unigraf CTS Test report. The complete logs can also be stored for later use or shared with colleagues as universally portable HTML files.

Compliance Testing

Unigraf’s AUX Channel Monitor is a mandatory tool for any engineer that wants to verify and/or debug Compliance Tests and Interoperability Test results. By analyzing the details of the source-sink interaction, the designer is able to fully confirm the behavior of both parties. When the content of each read and write are available in detail, there will be no room for guessing.

USB-C DisplayPort Alt Mode

With the special, Unigraf provided cable you can attach the DPA-400 directly between any two USB Type-C enabled devices to monitor DisplayPort Alt Mode related AUX Channel message transactions.


  • Compatible with all DP versions

  • Device-independent

  • Data interpreter with time stamps

  • Detect and parse all DPCD locations

  • Decode the Sideband CH Communication messages

  • Pocket size

  • USB controlled and powered


  • Silicon validation

  • Software debug and validation

  • Resolve interoperability problems

  • Monitoring and time measurement of events

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