Recently I have found that there are a network device called LPSS Serial Adapter (1) and LPSS Serial Adapter (2) in my network settings on my 2016 15" MacBook Pro, it has a phone (modem I guess) icon:

LPSS Serial Adapter

I tries to delete it, but it just comes back in a reboot. This doe not appear in any other Macs that I've own.

What is it?

P.S. It appears both on macOS Sierra 10.12.1 (16B2659) and 10.12.2 (16C67)

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    I'm seeing this on a brand new MBP15 Touch 2016 with nothing external every plugged in and without migration assistant! – Nic Cottrell Dec 23 '16 at 10:56

The LPSS adapters are related to a chip feature on the new 2016 MacBook Pros. I found these interfaces present immediately after setting up a new 15-inch 2016 Touch Bar model out of the box (before plugging in any peripherals or installing any drivers).

The following patent filing for the "low power subsystem" describes an interface through which a "secondary" processor can provide access to the system's memory while the primary processor is powered down:

The subsystem acts independently of the CPU, which would not be able to perform the necessary functions during low power mode. The subsystem allows the notebook to perform several functions while in the low power mode, such as, for example, act like a travel assistant for the user, provide entertainment, and make electronic purchases.


That is typically a USB to Serial (RS-232) adapter used in asynchronous communications (modem, serial port, console port, etc).

To "see" the device details in your hardware profile, open up "System Report" under About this Mac

enter image description here

If you disconnect everything from the computer, remove all the vpn and all other network interfaces, you could reboot in safe mode and determine all the Apple native interfaces. At that point, any new interfaces that show up will be due to profiles and third party software added. Just track those down by process of elimination.

  • I don't have anything plugged into my computer though – Tom Shen Dec 17 '16 at 16:13
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    That's what it is, however. – Allan Dec 17 '16 at 16:22
  • @Tom-Shen - you don't have a Thunderbolt Bridge plugged in, either, but it's still listed on the network pane! The pane lists all network devices you've plugged in, even if they're currently disconnected. – John N Dec 17 '16 at 16:25

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