Apple's Lightning Connector Uses Adaptive Technology to Dynamically Assign Pin Functions

lightning cable verticalWith Apple's new Lightning connector on the iPhone 5 dropping to just eight contact pins from the 30 pins seen in the original dock connector and gaining the ability to be inserted in either orientation, many have wondered just how Apple has been able to maintain most of the functions of the original dock connector. Others have wondered why Apple simply didn't shift to micro-USB, an existing standard in a comparable form factor.

Developer Rainer Brockerhoff has been examining Lightning's technical features and over the weekend outlined his thinking on how the "adaptive" nature of the Lightning connector highlighted by Apple during the technology's introduction at the iPhone 5 media event has enabled flexible functionality with a minimum of pins. Brockerhoff notes that the Lightning connector appears able to sense what kinds of devices are being connected and to use chips embedded in the cable to assign pin functionalities appropriate for each situation.

- The device watches for a momentary short on all pins (by the leading edge of the plug) to detect plug insertion/removal.

- The pins on the plug are deactivated until after the plug is fully inserted, when a wake-up signal on one of the pins cues the chip inside the plug. This avoids any shorting hazard while the plug isn’t inside the connector.

- The controller/driver chip tells the device what type it is, and for cases like the Lightning-to-USB cable whether a charger (that sends power) or a device (that needs power) is on the other end.

- The device can then switch the other pins between the SoC’s data lines or the power circuitry, as needed in each case.

- Once everything is properly set up, the controller/driver chip gets digital signals from the SoC and converts them – via serial/parallel, ADC/DAC, differential drivers or whatever – to whatever is needed by the interface on the other end of the adapter or cable. It could even re-encode these signals to some other format to use fewer wires, gain noise-immunity or whatever, and re-decode them on the other end; it’s all flexible. It could even convert to optical.

Double Helix Cables has now shared with AppleInsider a mapping of the pins on the two sides of the Lightning connector, demonstrating that this adaptive assignment of pin functions is required for the reversible nature of the plug.

"Take top pin 2 for example," he wrote in an e-mail to AppleInsider. "It is contiguous, electrically, with bottom pin 2. So, as the plug is inserted into the iPhone, if you have the cable in one way, pin 2 would go into the left side of the jack, flip it the other way and the same pair of pins is going to match up with the other side of the jack (as the electrical contacts in the iPhone's jacks are along the bottom)."

lightning pins
Mapping of pins in Apple's new Lightning connector

The adaptive nature of the Lightning connector may explain to some degree the rather high cost of cables and adapters for the new standard, as the $29 and $39 adapters for connecting 30-pin dock accessories to Lightning-equipped devices are required to contain hardware capable of working with the dynamically assigned pin functions. In addition, the adaptive nature indicates that the same Lightning interface could evolve over time to support new technologies within existing hardware.

Top Rated Comments

jtp098 Avatar
113 months ago
I guess I should cancel my ebay orders for third party adapters
Score: 57 Votes (Like | Disagree)
hlfway2anywhere Avatar
113 months ago
oh and all this time i thought they'd changed the connector for NO REASON whatsoever.

/s
Score: 46 Votes (Like | Disagree)
GeekLawyer Avatar
113 months ago
I guess I should cancel my ebay orders for third party adapters

I'd say that's a reasonable assumption.
Score: 36 Votes (Like | Disagree)
AppleFan115 Avatar
113 months ago
Amazing. When does the Samsung version come out?

Note: I do love Samsung TVs but sometimes the things they do just make me laugh. It will be extra funny when they do adopt it because they just bashed it in their printed ad.

Score: 35 Votes (Like | Disagree)
adildacoolset Avatar
113 months ago
*yawn*. I suppose it takes a bit more to get me excited. It's not like they found a new way to split the atom. Probably took an engineer a half day with his white board to map this out and make it so. I don't think this is very ground breaking and believe just like with anything it sounds a lot "cooler" and over-complicated when someone who likes to hear themselves talk explains it. Now make each connection with an encoded magnetic field and not a physical connection and I may be a bit more impressed. Until then, it's a basic evolution of a plug.

My friend, if one engineer could simply do that in half a day, then why was the patent granted 2 years ago, why didn't anyone else do it, and more importantly, why didn't you think before you type?
Score: 30 Votes (Like | Disagree)
Andrewdodson Avatar
113 months ago
I don't get it.
Score: 24 Votes (Like | Disagree)

Top Stories

2021 mbp hdmi slot 3d

2021 MacBook Pro Leaks Confirm Returning MagSafe and Ports

Friday May 14, 2021 3:06 am PDT by
Apple's upcoming MacBook Pro models are expected to feature a number of major changes such as larger display options and powerful new Apple silicon chips. Among the more surprising updates to this year's MacBook Pro models is the return of three ports that have been missing from the machines for over five years. Expected to come in 14- and 16-inch sizes, the 2021 MacBook Pro models are...
General Music and AirPod 3 Feature

Rumor: Apple to Announce Third-Generation AirPods and HiFi Apple Music Tier on May 18

Thursday May 13, 2021 10:32 pm PDT by
A new rumor suggests that Apple will announce the third-generation AirPods and the recently rumored HiFi, or high-fidelity Apple Music tier, on Tuesday, May 18, via a press release on its website. The new rumor comes from Apple YouTuber Luke Miani who shared the alleged exclusive news with the AppleTrack website. According to the YouTuber, Apple plans to release the next-generation AirPods...
m1 ipad pro early customer

M1 iPad Pro Arrives Early for Lucky Customer

Saturday May 15, 2021 11:57 pm PDT by
Days ahead of their expected launch and seemingly before official review embargoes lift, one lucky customer has already gotten their hands on the brand new 12.9-inch M1 iPad Pro. Reddit User PeterDragon50 Posted on Reddit, u/PeterDragon50 has already received their 12.9-inch iPad Pro through retailer Nebraska Furniture Mart. The Reddit user says they placed their order when pre-orders...
Twitter Feature

Twitter's 'Blue' Subscription Service May Cost $2.99, Will Offer Undo Tweet Option

Saturday May 15, 2021 11:08 am PDT by
Twitter has been working on some kind of subscription service since last summer, and Jane Manchun Wong, who often digs into new features coming in apps, has shared details on just what Twitter is exploring. Twitter's subscription service could be called Twitter Blue, and at the current time, it's priced at $2.99 per month. There will be a "Collections" section that allows users to save and...
magic mouse space gray discontinued

Apple Discontinuing Space Gray Mac Accessories Now That iMac Pro is Dead

Friday May 14, 2021 11:52 am PDT by
Following the discontinuation of the iMac Pro, Apple also appears to be discontinuing Space Gray "Magic" accessories that it sold separately alongside the iMac Pro. The iMac Pro was the only Space Gray Mac, and Apple designed special matching accessories for it. The Space Gray Magic Mouse 2, Magic Keyboard, and Magic Trackpad all now say "While supplies last" in small wording at the bottom...
tile amazon sidewalk integration

Apple Says Tile Trackers Sold Poorly in Apple Stores

Friday May 14, 2021 4:53 am PDT by
Earlier last month, Spotify, Tile, and Match (owner of Tinder), testified at an app store antitrust hearing spearheaded by the U.S. Senate. During the hearing, Spotify called Apple's App Store "an abusive power grab," while Tile said Apple uses its platform to "unfairly limit competition for its products." Now, in response to their testimonies, Apple's vice president and chief compliance...
apple music change forever

Apple Music Teaser: 'Get Ready – Music is About to Change Forever'

Sunday May 16, 2021 2:39 pm PDT by
The Browse tab in the Music app across Apple's platforms has started displaying a prominent teaser hinting at an upcoming major announcement for Apple Music. Under the heading "Coming soon," the headline says "Get ready – music is about to change forever." An accompanying "Tune-In Video" simply shows an animated Apple Music logo. Rumors have indicated that Apple is preparing to launch a...
Top Stories 60 Feature

Top Stories: M1 iMac Benchmarks, iPhone Battery Life Tips, Colorful MacBook Air?

Saturday May 15, 2021 6:00 am PDT by
Anticipation is building for the new iMac and iPad Pro models, which have started shipping out ahead of a launch around May 21. Benchmarks for the new machines are starting to come in, and the M1 chips inside of them are registering at around the same figures seen with other M1-based Macs, making for significant upgrades over previous-generation models. This week also saw some rumors about...
syng cell alpha

Longtime Apple Designer Christopher Stringer's Latest Project Is a High-Fidelity Speaker With AirPlay 2

Friday May 14, 2021 7:30 am PDT by
Christopher Stringer, a key member of Jony Ive's design team who spent 21 years at Apple before departing in 2017, is resurfacing today with his new venture Syng, which seeks to make an impact in the high-end audio market. Stringer, who contributed to many of the most iconic product designs in Apple's history, announced his plans roughly a year ago, and Syng is today introducing its flagship ...
google photos

PSA: Google Photos Unlimited Storage Ends Next Month, Here's How to Export Your Pictures to iCloud

Thursday May 13, 2021 5:26 am PDT by
For as long as it's existed, Google Photos has offered free unlimited storage for uploading images at a reduced yet good enough quality for most users. From June 1, 2021, however, all photos and videos uploaded to Google accounts will count against users' cloud storage. If you've been relying on Google to back up your media library, it may be time to move that content elsewhere. This article...