science

Unified Display Interface

Unified Display Interface is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Unified Display Interface rather than just read about it. In short: Unified Display Interface (UDI) was a digital video interface specification released in 2006 which was based on Digital Visual Interface (DVI). It was intended to be a lower cost implementation while providing compatibility with existing High-Definition Multimedia Interface (HDMI) and DVI displays.

Key takeaways

Unified Display Interface belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Unified Display Interface to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Unified Display Interface from memory before moving on to harder problems.

Reference excerpt

Unified Display Interface (UDI) was a digital video interface specification released in 2006 which was based on Digital Visual Interface (DVI). It was intended to be a lower cost implementation while providing compatibility with existing High-Definition Multimedia Interface (HDMI) and DVI displays. Unlike HDMI, which is aimed at high-definition multimedia consumer electronics devices such as television monitors and DVD players, UDI was specifically targeted towards computer monitor and video card manufacturers and did not support the transfer of audio data. A contemporary rival standard, DisplayPort, gained significant industry support starting in 2007 and the UDI specification was abandoned shortly thereafter without having released any products.

Development On December 20, 2005, the UDI Special Interest Group (UDI SIG) was announced, along with a tentative specification called version 0.8. The group, which worked on refining the specification and promoting the interface, was led by Intel and included Apple Computer, Intel, LG, NVIDIA, Samsung, and Silicon Image Inc. The announcement of UDI lagged the DisplayPort standard by a few months, which had been unveiled by the Video Electronics Standards Association (VESA) in May 2005. DisplayPort was being developed by a rival consortium including ATI Technologies, Samsung, NVIDIA, Dell, Hewlett-Packard, and Molex. Fundamentally, DisplayPort transmits video in packets of data, while the preceding DVI and HDMI standards transmit raw video as a digital signal; UDI took an approach closer to DVI/HDMI. The UDI specification 1.0 was finalized and released in July 2006. The differences between UDI and HDMI were kept to a minimum since both specifications were designed for long-term compatibility. Again, UDI lagged DisplayPort by a few months, which had released its finalized version 1.0 specification in May 2006. The group changed its title in late 2006 from "special interest group" to "working group" and contemporary press coverage noted that "UDI is weak when it comes to industry support", accurately predicting the future DisplayPort/HDMI duopoly. In early 2007 Intel started supporting the rival DisplayPort standard; anonymous sources stated the licensing fees associated with HDMI and incorporation of HDCP into DisplayPort swayed Intel's support. Other vendors started to use HDMI version 1.3, and both Intel and Samsung withdrew their support from UDI. There have been no announcements made about UDI since early 2007 and the UDI website became no longer operational after 2007, and it appears the UDI standard was abandoned before products were released.

Technical There were two UDI implementations: "external profile" (for desktop computers and displays) and "embedded profile" (for the internal display of a laptop computer). Under the external profile, data was transmitted using three differential data pairs and one differential clock pair using the TMDS encoding scheme. The external profile is considered an extension of HDMI and is backwards-compatible with HDMI Rev. 1.2 displays; however, UDI does not carry audio information as it is targeted towards high-resolution computer monitors instead. As HDMI is itself an extension of DVI with HDCP, UDI external profile is compatible with these standards as well. The embedded profile was slightly different, using either one or three differential pairs, each of which carried both data and clock information. The embedded profile uses an ANSI 8b/10b encoding scheme instead. UDI provided higher bandwidth than its predecessors (up to 16 Gbit/s in its first version, compared to 4.95 Gbit/s for HDMI 1.0) and incorporated a form of digital rights management known as HDCP.

Connector The external and embedded connector implementations were electrically compatible and physically similar, each with a single row of contacts, but they had different form factors and contact counts. The "embedded" implementation was only specified for the display panel interface and had a single row of 26 contacts, while the "external" implementation had a single row of 22 contacts inside a metal shield with a physically keyed rectangular cross-section, resembling the USB Type A connectors. The contacts were spaced on a pitch of 0.6 mm (0.024 in) (external) and 1.0 mm (0.039 in) (embedded). Three of the contacts were reserved for future upgrade possibilities. Transmit and receive plugs and receptacles were different physically, similar to peripheral cables with USB-A and USB-B on each end, requiring the UDI cable to be plugged in one way only. Bidirectional communication worked at a much lower data rate than that available for the single direction video datastream.

Notes

References

External links "Unified Display Interface Specification, Revision 1.0a Final" (PDF). Unified Display Interface Working Group. July 12, 2006. Archived from the original (PDF) on September 28, 2007. Retrieved February 2, 2023. US abandoned 2007257923A1, Whitby-Strevens, Colin, "Methods and apparatus for harmonization of interface profiles", published November 8, 2007, assigned to Apple Inc.

Illustrations

Worked examples

Example 1 — a first encounter with Unified Display Interface

Start with the simplest possible case. Write down what Unified Display Interface claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Unified Display Interface before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Unified Display Interface ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Unified Display Interface

In research: Unified Display Interface appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Unified Display Interface in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Unified Display Interface is common in secondary-school and first-year university syllabi. It links to neighbouring topics Digital display connectors, High-definition television, so understanding it makes those chapters shorter.
In everyday life: Look for Unified Display Interface outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Unified Display Interface in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Unified Display Interface means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Unified Display Interface out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Unified Display Interface in simple terms?

Why does Unified Display Interface matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Unified Display Interface?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Unified Display Interface.