MBP & External Monitor - Ports?

Discussion in 'MacBook Pro' started by JABacchetta, Mar 21, 2016.

  1. JABacchetta macrumors newbie

    Nov 12, 2012
    I've got a MBP (2015) and am looking to purchase the Dell UltraSharp U3415W. I still don't really understand how all of the different connections interact.

    What's the most efficient way (i.e. least amount of cords and adapters) to make sure that a) my MBP is connected to the monitor b) is charging c) is connected to an ethernet cable d) is connected to an external keyboard?

    The Dell has the following connections:
    • 1x HDMI
    • 1x MHL
    • 1x Mini Display Port
    • 1x Display Port (v 1.2)
    • 1x DisplayPort (MST)
    • 4x USB 3.0 Downstream
    • 2x USB 3.0 Upstream
    • 1x Audio
    From what I understand, connecting the DisplayPort (MST) to a thunderbolt via an adapter will produce the best quality and allow for the MPB to be charged, too. Is that correct?

    If I plug the ethernet cable into a USB adapter, and then plug that into one of the Dell's USB upstream ports, will my MBP be connected to the internet?

    Then just use the other upstream port for my external keyboard?

    I also have an external mouse that works with usb and also bluetooth. I assume the bluetooth will still work with the MBP screen shut? If not, what would I do with that, considering the two upstream ports would be occupied? Buy an additional adapter with more upstream ports?
  2. JTToft, Mar 21, 2016
    Last edited: Mar 21, 2016

    JTToft macrumors 68040

    Apr 27, 2010
    Aarhus, Denmark
    Lots of questions here. For the screen connection, you'd do a cable from the Thunderbolt port on your MBP to the DisplayPort on the monitor (not the MST one, which is an output from the monitor to another monitor). The U3415W comes included with a suitable mDP to DP cable.

    No connection between the computer and the monitor will carry power to either device. You need your MagSafe.

    You are correct on the USB-Ethernet adaptor, except you'd need to use a downstream USB port (of which there are 4). The upstream port is for connecting to your MBP.
    Same thing for external keyboard and mouse.

    Bluetooth as well as every other function of your MBP will still work with the screen shut and the machine connected to the monitor. It's what's called closed-clamshell mode.

    So all in all, you would have the following connections out from your MacBook Pro:
    - Mini DisplayPort to DisplayPort cable going to the monitor for display signal.
    - USB 3.0 cable going to the monitor for data connection to the USB hub.
    - MagSafe for power.

    You'd then plug your USB to Ethernet as well as your mouse and keyboard into the monitor's downstream USB ports.
  3. JABacchetta thread starter macrumors newbie

    Nov 12, 2012
    Awesome, thank you for the detailed reply!
  4. JABacchetta thread starter macrumors newbie

    Nov 12, 2012
    OK, so I've got this setup going and everything appears to be working except for one issue. There's severe lag with the keyboard and mouse. It starts off working fine, and then they'll randomly just start lagging to the point where they're unusable. The only way to get them to start working properly again is to disconnect and reconnect.

    Any idea what the issue might be?
  5. JTToft macrumors 68040

    Apr 27, 2010
    Aarhus, Denmark
    - Both mouse and keyboard connected via USB on the monitor's USB ports? Both via cable, or do they use wireless adaptors?

    If they use adaptors or other wireless connectivity, it may be USB 3.0 interference.
  6. JABacchetta thread starter macrumors newbie

    Nov 12, 2012
    Yes, I'm using USB wireless receivers for both. I can actually use Bluetooth with the mouse, which I've since enabled.

    However, I just realized that the lag was only coming from keys on the right side of my keyboard. As it turns out, moving the entire keyboard closer to the receiver fixed the problem. Unfortunately, this isn't really a solution, because the keyboard literally has to be on the left side of the monitor and about a foot away from it.

    My original keyboard position was in the middle of the monitor at about three feet away. No idea why this doesn't work — Logitech says their receivers can work up to 30 feet away.

    Not sure if this is a result of bad product design on Dell's part? Whether it's something specific inside the monitor that's blocking the connections or whether it's just the massive size of the monitor itself... in which case, maybe there should have been a hub on the front.

    Is there anything that can be done to fix this, other than an external hub?
  7. JTToft macrumors 68040

    Apr 27, 2010
    Aarhus, Denmark
    - Get a new keyboard, one that doesn't use those silly Logitech USB receivers.
    I can't see it being a problem with the monitor.
  8. Fishrrman macrumors G5


    Feb 20, 2009
    I'd suggest a WIRED USB keyboard.
    Wireless mouse is ok.

    Actually, a wired keyboard with 1 or 2 USB ports is best.
    Then, plug the "receiver" for the wireless mouse into the keyboard port, where it will be "closest" to the mouse.
  9. LYNQ macrumors newbie


    Jun 13, 2016
    You could use our product to connect to your monitor via HDMI. It supports HDMI 2.0 for 4K displays as well.
    You can take a look at our website: www.lynqnow.com

Share This Page