The DisplayPort 2.1 specification is the newest DisplayPort standard from VESA. The specification was released to the public on October 17, 2022. The newest DisplayPort spec is fully backwards compatible with all the previously released version. This post discusses protocol/encoding changes, new link rates and cable design. Protocol & Encoding Changes for DisplayPort 2.1 Specs The DisplayPort 1.4 specification and previous specification versions used an 8b/10b encoding for the transmission of display information. 8b/10b has an overhead of 20%, meaning 20% of the data sent is being discarded and is irrelevant to the image being displayed. DisplayPort 2.0/2.1 added the ability for devices to use a 128b/132b encoding method. The new 128b/132b has a much lower overhead of just 3%, meaning more relevant data is being displayed instead of being discarded. Another important point of using the 128b/132b encoding enables alignment to other cutting-edge technologies like USB4, Thunderbolt 3/4 and PCI Express 3.0-5.0. The alignment allows IC designers to use similar IC components and technologies that have been previously designed and implemented. New Link Rates – DisplayPort 2.1 vs. 1.4 The new data rates more than double the data transmission rate enabling much higher resolution displays with higher refresh rates, from a DP 1.4 maximum single display output of 8K (7680 x 4320) display @30Hz and 24 bpp 4:4:4 (no compression) compared to a DP 2.1 maximum single display output of 10K (10240×4320) display @60Hz and 24 bpp 4:4:4 (no compression). For DP 1.4/1.2 devices are required to support all link rates below its the maximum stated link rate. For example, a DP device that supports the 8.1 Gbps/lane link rate must support 5.4, 2.7, and 1.62 Gbps/lane link rates. For a DP 2.1 device that supports 128b/132b DP channel-coded link rates, support for the 10 Gbps/lane link rate is mandated; support for the 13.5 and 20 Gbps/lane link rates is optional. Support for the 13.5 Gbps/lane link rate is optional for a DP device that supports the 20 Gbps/lane link rate. For example, if a DP 2.1 device supports a link rate of 20 Gbps it would also need to support 10 Gbps but 13.5 Gbps would be optional. When using an 8b/10b DP channel coding there are two protocols for transmission of data, Single Stream Transport (for direct connection to only one display) and Multi Stream Transport (enables one DP source port to connect to multiple DP sink devices using a MST hub (Branch Device)). DisplayPort 2.1 only uses a Multi Stream channel coding which means regardless of if the only one display is connected, or multiple displays are connected, the same pixel data-to-DP link symbols mapping is used. Cable Design Cables are a critical part of the connection between the DP source and DP sink. As the DP link rates increase in speed, the build quality and performance become even more critical. The DP 2.1 spec has broken the DP cables into 4 types: DP80, DP40, DP8K, HBR To support the higher link rates new enhanced Full-sized DP and mDP connectors were required. The enhanced full-sized DP connectors are broken into two types, Type 1 is designed to support up to 4-lane UHBR13.5 well Type 2 is designed to support up to 4-lane UHBR20. Enhanced full-sized DP connectors use mandatory paddle card (PCB) to ensure plastic dielectric properties, angle and length of pins meet signal loose requirements. The enhanced full-sized DP receptacles require more PCBA space because of the increased shielding and connection pin layout. DP80 cables are required to support link rates UHBR20, UHBR13.5 and below. DP40 cables are required to support UHBR10, they use the same enhanced connectors as DP80 which allows for longer cable designs and require the same mechanical requirements. DP40 and DP80 cables along with USB-C cables will contain cable ID mechanisms. Systems must not enable speeds above HBR3 without first verifying that the cable is the correct type to support the desired speeds. All new DP cables are required to be backwards compatible with existing DP 1.2/1.4 Source and Sink devices, if using the full-sized DP or mDP connectors. Conclusion As you can see, the DisplayPort 2.1 specs for updated link speeds, new 128b/132b encoding and enhanced connectors will allow support for extremely high-resolution screens of the future and beyond. With the standard support of MST required in DP 2.1 will enable the possibility of high resolution multi output devices across multiple operating systems. With the added features of DP 2.1, DP will continue to show itself the market leader in the PC industry for many years to come. Learn more about selecting cables and adapters for your performance-focused deployments here: 8K UHD Solutions for Your Business