Apple said the new Lightning connector is 8 signals design but is there an additional ground aside from the 8 pins? Because this would mean it could support USB 3.0 in the future (USB 3.0 uses is 9 pins). (It could not support Powered USB 3.0 that is 11 pins).


2 Answers 2


If you count the shield on USB 3.0, the "9 pin" version actually requires 10 pins, as the shield, while typically grounded, is not actually used as the signal-ground (and it cannot be used as such).

As such, if the lightning connector indeed has only 8 pins, there is no way it can support USB 3.0 while properly complying with the USB spec.

I would guess that if it supports USB 3.0, it would be with non-standard USB extension, much as many of apple's other USB addons (like their high-current charging facilities).

I'd like to further note that, from an electrical engineering standpoint, using the casing (which is called the shield) for anything but, well, shielding is considered very bad practice.

The entire point of shielding is to basically absorb any interference before it can each the inner conductors. If you are relying on the shield for carrying a meaningful signal (and ground is indeed a meaningful signal), it is no longer effective as a shield.

If it does support USB 3.0, I would hope they open the connector mechanical design up for wider adoption, as the current USB 3.0 micro connector is horribly designed mechanically.

  • 2
    Here is proof that a question of marginal quality (but thankfully short, documented and to the point), not really clear that there is an actual problem the OP is facing other than "teach me about Y", can be saved by an awesome answer and be totally useful in practice. Kudos @FakeName
    – bmike
    Sep 20, 2012 at 15:15
  • @bmike - Wait, this is a great answer? Huh. I totally wrote it off-the-cuff, with basically no real thought.
    – Fake Name
    Sep 20, 2012 at 19:18
  • It's short, sweet and cuts right to the chase. Addresses what needs to be said and ** drops microphone and walks off stage **
    – bmike
    Sep 20, 2012 at 19:30
  • @FakeName It is a great answer. I hope you don't mind I removed the (mild to me) profanity.
    – Cajunluke
    Sep 20, 2012 at 20:14
  • @CajunLuke - I expected someone would edit it out. I mostly really, really dislike the micro-b USB3 connector. I have multiple external hard-drives that use it, and they all have reliability issues.
    – Fake Name
    Sep 22, 2012 at 19:36

As Apple has already USB 3.0 on its newer computer models, it is strange that the lightning connecter doesn't already support USB 3.0. The new design features a 9-pin, 8-signal arrangement that may be compatible with future USB 3.0. -- So it's (8 + 1) pins.

Hopefully "Lightning" will support USB 3.0 or Thunderbolt speeds. That would be a great reason for Apple not to have used Micro-USB (which in its industry standard design is limited to USB 2.0 speeds since it lacks the extra pins needed for USB 3.0).

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    The iPhone 5 probably doesn't support USB 3.0 because the chipset to do so would be big and power-hungry. And the Lightning connector has nowhere near enough contacts to support Thunderbolt, even assuming they ever use PCI-Express in an iPhone, which is doubtful.
    – Cajunluke
    Sep 20, 2012 at 15:07

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