MaximumPC (January 2011) has an article on a new connection standard, HDBaseT. It’s a single Ethernet cable that can provide HDMI, power, and data 100 meters. It’s interesting to see how they knock down the data rate of HDMI from 10.2Gb/s to around 8 by skipping the error correction process which they say accounts for almost 3Gb/s of bandwidth.
“… [pulse-amplitude modulation] functions in the same basic manner as in gigabit and 10-gigabit Ethernet and uses the same cables, HDBaseT follows a proprietary modulation scheme. Only the physical cables are used, not the underlying Ethernet packet structure. Even HDBaseT’s 100Mb/s Ethernet gets encoded in this way, although an HDBaseT port can revert to plain Ethernet, skipping HDMI and other features if you accidentally (or deliberately) plug into a traditional Ethernet network. HDBaseT uses its own physical switches, too.”
Something to be aware of, the article says the standard was designed to span 100 meters because that’s what Ethernet’s established limits are, you can cascade 5 active switches to get 500 meter, BUT (big BUT) “Content providers also get a say in your distance; an optional setting could keep you to 100 meters total so you don’t broadcast Blu-ray movies to the neighbors. [The Alliance] says hardware could activate the restriction based on a DRM flag embedded in the content.”
So when the time comes and we start implementing this stuff don’t assume you can cascade switches. DRM comes into play here and can limit us to 100 meters (or less?) if the content provider wants.
