ajookk
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Latitude 7490 - Two monitors connected directly (lid closed)

Hi,

I have an i5 - 8th gen (with UHD 620) Latitdue 7490.
I'd like to connect two monitors (34' ultrawide and 24', both at 1080p) directly to the laptop - one via the USB Type C port and the other one via the HDMI port.
The laptop lid remains closed (so that's a total of 2 displays in an extended desktop mode).

Is this possible or am I forced to buy a dock like WD15 (which I really prefer not to...)?


Thanks!

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8 Replies
jphughan
5 Tungsten

Re: Latitude 7490 - Two monitors connected directly (lid clo

Yes, that setup will work, although you’ll likely need to set the Lid Close Action to “Do Nothing” so your system doesn’t go to sleep when you close the lid. You’ll then need to put the system to sleep manually. A dock allows you to work with the lid closed WITHOUT making that change because the dock gives you an external Power button to control the system, meaning you can wake it up while the lid is closed, and therefore you won’t trigger the sleep action because the lid is already closed (the Lid Close Action only occurs when the lid transitions from open to closed).

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jphughan
5 Tungsten

Re: Latitude 7490 - Two monitors connected directly (lid clo

A few additional notes after my post above:

- For the USB-C connection, it will have to be a basic USB-C to DisplayPort cable, plugged directly into the system, NOT through a mini-dock that offers other connectivity, because that would cut available display bandwidth in half, which I’m fairly sure won’t be enough to run that ultrawide resolution.

- The WD15 would be a bad choice for you for the reason above. Since it uses regular USB-C and offers all of that extra connectivity, it may not have enough display bandwidth to run that display, and it absolutely wouldn’t have enough to run both. The TB16 would, but that requires your system to have Thunderbolt 3, which is optional on the 7490.

- Based on a thread I read about the very similar 7480, there’s a good chance that while using USB-C for video output, you can’t use VGA. Just be aware.

- If it helps, you might be able to get away with setting your Lid Close Action to “Do Nothing” only for when your system is connected to AC power, as long as you connect power before closing the lid. Just remember that if you have the lid closed and then take your laptop away with you, it may be fully awake. You can damage laptops by putting them into laptop bags while fully powered up.

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ajookk
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Re: Latitude 7490 - Two monitors connected directly (lid clo

Thank you for the detailed replies. 

Unfortunately I don't have the Thunderbolt 3, just a DisplayPort over USB Type C.
I want to clarify that I always work with the lid closed. Now I have the LG ultra wide 34" (2560*1080 @ 59hz) connected using the HDMI port of the laptop.

So basically, my only option is connecting each screen to its own port on the laptop (one HDMI and one DisplayPort over USB Type C), since the DP over Type C won't be able to handle the bandwidth. 
Please correct me if i'm wrong Smiley Happy 
Are you certain regarding the bandwidth issue? I was close to ordering the WD15 dock anyway Smiley Very Happy 


Thanks!

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ajookk
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Re: Latitude 7490 - Two monitors connected directly (lid clo

Thank you for the replies! So basically my only option with my 2560*1080 and 1920*1080 displays is having them both connected separately directly to the HDMI and DisplayPort over USB type C, on the Laptop's body. Please correct me if i'm wrong Smiley Happy Thanks
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jphughan
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Re: Latitude 7490 - Two monitors connected directly (lid clo


@ajookk wrote:
Thank you for the replies! So basically my only option with my 2560*1080 and 1920*1080 displays is having them both connected separately directly to the HDMI and DisplayPort over USB type C, on the Laptop's body. Please correct me if i'm wrong Smiley Happy Thanks

Oh, your ultrawide is only 2560x1080? I thought it was 3440x1440 or 3840x1600. But in that case, you may have another option. If both of your displays have DisplayPort or Mini-DisplayPort inputs and one of them has a DisplayPort OUTPUT meant for daisy-chaining, then you could connect the two displays to each other and then connect the first display to your system via USB-C, which can be used to drive both. I run dual 2560x1440 displays from a single USB-C cable this way.

But other than that, if your 7490 does not have Thunderbolt 3, then yes direct connecting both displays is your best option, because the WD15 would only be able to run one of those displays at a time (so you’d still be direct connecting the other), and the only remaining option would be adapters or docks that use technology like DisplayLink instead of actually using native GPU outputs, but DisplayLink has some notable drawbacks.

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ajookk
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Re: Latitude 7490 - Two monitors connected directly (lid clo

Hi again Smiley Happy Unfortunately both screens lack the DisplayPort outputs. Only the LG ultra wide has a DP input, but not output. The other one has only HDMI and VGA inputs. So I guess that really limits my options to one Smiley Happy Quick question: I have a USB Type C input on the LG ultrawide (it has the DP logo next to it). A simple USB Type C to USB Type C cable should be enough to connect the screen? Or should I buy a simple USB Type C to HDMI adapter and then using a standard HDMI to HDMI cable to connect it. There are also options like this one: https://plugable.com/products/usbc-dp/ I'm a bit unfamiliar with using these adapters and using a Type C USB for display, so i'm not really sure what's the best (and cheapest) way to do it. Thanks again for the detailed replies!
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jphughan
5 Tungsten

Re: Latitude 7490 - Two monitors connected directly (lid clo

If your display has a USB-C input, then yes a USB-C to USB-C cable will work as long as you get one that specifically mentions it supports USB 3.1 Gen 1 or DisplayPort Alt Mode. There are some USB-C cables that only support USB 2.0 because they’re meant primarily for charging and minor data transfer traffic, and those won’t work. Cables that support USB 3.1 Gen 2 will work, but you don’t need that, and those cables will limit your length options. Possible perks of using the USB-C connector on the display rather than the others is that depending on your display’s implementation, a) the USB-C cable might carry USB data to your laptop, so if you have USB devices connected to the display, you won’t need to connect a separate USB cable to your PC to use them, and b) the USB-C cable might carry power to charge your laptop. Not all USB-C displays offer this because it requires the display itself to have a larger power supply than would otherwise be be necessary, but if you find that your 7490 charges while connected to the display via USB-C, that’s a nice bonus.

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ajookk
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Re: Latitude 7490 - Two monitors connected directly (lid clo

Thank you very much for your replies!

I ended up connecting the ultra wide using a Type C to HDMI adapter, and the other screen using the HDMI port. All works great and i'm pleased.

Thanks again and have a good day!

 

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