science

PDMI

PDMI 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 PDMI rather than just read about it. In short: PDMI (Portable Digital Media Interface) is an interconnection standard for portable media players. It has been developed by CEA (Consumer Electronics Association) as ANSI/CEA-2017-A standard Common Interconnection for Portable Media Players in February 2010.

Key takeaways

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

Reference excerpt

PDMI (Portable Digital Media Interface) is an interconnection standard for portable media players. It has been developed by CEA (Consumer Electronics Association) as ANSI/CEA-2017-A standard Common Interconnection for Portable Media Players in February 2010. Chaired by David McLauchlan from Microsoft, the standard was developed with the input or support of over fifty consumer electronics companies worldwide.

Development and history CEA-2017-A is the new revision of the earlier ANSI/CEA-2017 standard adopted in July 2007, which used a proprietary serial protocol based on Media Oriented Systems Transport (MOST) in-vehicle network; the 2007 revision has seen only marginal use in actual devices. New CEA-2017-A devices are not compatible with devices manufactured under the 2007 revision. PDMI connector is intended to serve as a common interconnection between docking devices and displays and portable/nomadic devices with media playback capability. Intended host devices include docking stations for home A/V equipment, in-car entertainment systems, digital media kiosks, and hotel/in-flight entertainment systems, where PDMI aims to replace the ubiquitous iPod cradle connector. PDMI uses a 30 pin receptacle with approximate size of 2.5 mm by 22 mm; a cradle-style connector is also defined. The PDMI connector includes the following electrical interfaces:

2-lane DisplayPort v1.1a with AUX Channel, Hot Plug Detect, and 3.3 V power line USB 3.0, USB 2.0, and USB On-The-Go Analog stereo line-out for legacy audio HDMI CEC for remote control High output power line from both host and portable device DisplayPort component provides data rate of 4.32 Gbit/s and supports up to 1080p60 video and 8-channel audio playback on an attached display device, as well as EDID and display control commands. DisplayPort signal can be converted to HDMI format using active converter circuitry in the dock or external signal conversion adapter powered by 3.3 V DisplayPort power. Power supply from both the host (docking station) and portable device allows for supporting the portable device with power and battery charging, as well as supporting accessories from the portable device. USB 3.0 "SuperSpeed", USB 2.0, and USB On-The-Go support file transfer and device control, as well as device-to-device intercommunication.

Devices that use PDMI

The first mass-production device from a major manufacturer to incorporate PDMI is the Dell Streak, a 5 in (130 mm) tablet device running the Android operating system version 1.6 through 2.2.

Pinout

References

External links Purchase Standards

CEA-2017 Rev A, Common Interconnection For Portable Media Players (PDMI), $75. CEA-2017.1 Rev 7, Serial Communication Protocol For Portable Electronic Devices, $156. Slides

DisplayPort Technical Overview; Slides; May 2010, contains slides about PDMI Announcements

CEA Announced Portable Media Connection Standard CEA may spawn standards effort for handhelds

Illustrations

Worked examples

Example 1 — a first encounter with PDMI

Start with the simplest possible case. Write down what PDMI 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 PDMI 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 PDMI 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 PDMI

In research: PDMI 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 PDMI 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: PDMI is common in secondary-school and first-year university syllabi. It links to neighbouring topics Audiovisual connectors, Digital display connectors, Electronics standards, so understanding it makes those chapters shorter.
In everyday life: Look for PDMI 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 PDMI in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PDMI 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 PDMI out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PDMI in simple terms?

Why does PDMI 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 PDMI?

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 PDMI.