Pros & Cons of HDMI Baluns

Using HDMI baluns has become common practice, but there are problems with this solution.

Jeff Boccaccio

Using an HDMI over Cat 5 cable solution (commonly referred to as a balun) has become common when CE pros look to transport HDMI data over distances longer than 5 to 10 meters.

It has the added benefit of allowing field termination with relatively good overall performance. That is not to suggest that there are no problems with this solution.

Let’s look at this alternative HDMI transport mechanism and start dissecting its parts.

For starters, if HDMI was truly designed for Cat 5, don’t you think somebody would have introduced it a long time ago? The inside story on the balun category is that Cat 5 embodies some similar attributes of the technology used to construct an HDMI cable, including:

  • A twisted topography (twisted pairs)
  • Impedance of 100 ohms
  • Good bandwidth
  • Relatively good timing
  • Four-pair configuration, making it pretty adaptable by using two wires

Manufacturers don’t necessarily want to admit this, but there are downsides to using category cable as an HDMI transport mechanism, including:

  • A huge and largely overseas manufacturing base that may yield poor consistency
  • A high sensitivity to distortion from factors such as abuse, wire management and foreign objects
  • Poses a serious challenge to the HDMI operating envelope