108 PCWorld DECEMBER 2019FEATURE HDMI VS. DISPLAYPORT
and certification levels, as shown below.
RBR DisplayPort cable (Reduced Bit Rate)
6.48Gbps (DisplayPort 1.0)
Standard DisplayPort cable for HBR
(High Bit Rate) 10.80Gbps and HBR2 (High
Bit Rate 2) 21.60Gbps
DP8K cable for HBR3 (High Bit Rate 3)
32.40Gbps (DisplayPort 1.3) and UHBR 10
(Ultra High Bit Rate 10) 40Gbps (DisplayPort 2.0)
Again, try your cable before you opt for
something more expensive, whether it has a
label or not. Also, practical experience has
shown that VESA’s length specs are very
conservative, depending on resolution.
Active copper DisplayPort cables drawpower from the DisplayPort connector to
operate a signal amplifier embedded in the
connector, and they can be considerably
longer than passive cables.
Pin 20 in the DisplayPort spec is used for
power over Thunderbolt, and was originally
used with DisplayPort. However, it caused
issues and was dropped from cables if not the
connectors. That’s the reason there are both
Thunderbolt and DisplayPort cables, rather
than one type. Older non-certified
DisplayPort cables might have pin 20
connected. Be careful with them, or sell them
to someone with a Thunderbolt setup.
As to cable lengths, the shortest you canUSB-C features an alternate mode that allows the use of alternative transport protocols, such as
DisplayPort and HDMI.