Black Box Explains… DisplayPort (DP) Interface
DisplayPort is the most recent digital video interface to be developed for commercial use. It is a standard for PCs.
The DisplayPort standard was designed as a replacement for DVI connectors on computer hardware. The connector is smaller and screwless for easier installation. The connector still has a locking mechanism to hold it in place, addressing a weakness of the HDMI connector. It is similar in specifications to HDMI, but it is more common for computers than for televisions.
DisplayPort uses a packet type of interface, just like an IP network does. The network-like design means a single connection can send multiple streams, so a single DisplayPort port can connect to more than one display.
DisplayPort uses very high speeds, enabled by the packet-type delivery that is implemented through chipsets. One can think of it as a high-speed network for digital video. DisplayPort uses a serial interface with up to four main data lanes that can carry multiplexed video and audio data. Each data lane supports a raw data rate of 1.62 Gbps, 2.7 Gbps, or 5.4 Gbps (DisplayPort 1.2 or later). Additionally, unlike with DVI, an audio channel is supported—up to eight channels of 16- or 24-bit at 48 KHz, 96 KHz, or 192 KHz.
DisplayPort and DVI
DisplayPort and DVI use different signal processing methods, but converting between the two can be done with adapters. Some DisplayPort ports have internal components to make them passively compatible with DVI signals, but this is not a DisplayPort requirement. This is known as Dual Mode, or DP++. It appears that DisplayPort is converted to DVI, but the hardware outputs a DVI signal through a DisplayPort port. If the hardware in use can’t output the DVI signal, then a DisplayPort-to-DVI adapter won’t operate. Users should look for the DP++ symbol.
DVI offers no audio support, which gives another advantage to DisplayPort. An additional advantage for DisplayPort is that packetizing data lowers demand on bandwidth. DVI uses separate data channels for each color, requiring high bandwidth all the time.
DisplayPort and HDMI
Since HDMI and DVI use the same signal technology, HDMI and DisplayPort have similar compatibility issues noted already. HDMI is the digital standard targeted to home theater, and DisplayPort was developed for use with computer electronics. However, feature-wise, DisplayPort is very similar to HDMI, including the inclusion of the HDCP content-protection standard. Some differences include:
- DisplayPort has a maximum bandwidth that is larger than the maximum bandwidth of HDMI (10.8 Gbit/sec, compared to HDMI at 10.2).
- DisplayPort supports the DPCP (DisplayPort Content Protection) standard in addition to HDCP.
- DisplayPort is an open standard, available to all manufacturers at no cost; HDMI is licensed, which raises costs.
- DisplayPort supports resolutions up to 4K.