My internet is down right now.

I have roku ultra, which I can cast to from my phone, but the Roku needs internet access.

I would like a solution where I can cast or mirror my phone screen to my TV, without needing access to the internet, except by the phone via the cell network.

That way, I can run YouTube TV on my phone and cast to the TV screen.

Is that possible?

What phone do you have?

Android, Samsung Galaxy 10

Why do these products, Chromecast, Roku, etc... require a connection to the internet if all I'm doing is using it to cast or mirror my screen?

I went through the process of mirroring my phone screen on Roku only to have it tell me it could not do it because it could not connect to the internet.

If there is no internet, they can't send all that precious personal data of yours to their servers. Since you're not cooperating, neither will they.

You should be able to get a USB-C to HDMI cable to plug the phone into the TV.

It works on a S9 at least.

Thanks.

third coast.. said:

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Does your TV have wifi direct? That's how I cast to my tv from my phone while I am out at sea.

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I tried that. The phone said it was connected, but the TV never confirmed it.

Also, even if I could connect, I have to use wifi on the phone, which means it wants to stream via the wifi radio and not cellular, which won't work because I don't have internet.

bco2003 said:

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You should be able to get a USB-C to HDMI cable to plug the phone into the TV.

It works on a S9 at least.

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This is the one I have:

USB C to HDMI Cable(4K@60Hz) https://www.amazon.com/dp/B075V5JK36?ref=ppx_pop_mob_ap_share

Turn on your phone hotspot and use that as "wifi" for your TV.

Cassius said:

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Why do these products, Chromecast, Roku, etc... require a connection to the internet if all I'm doing is using it to cast or mirror my screen?

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I know with the Chromecast, that's not how they work. It doesn't mirror your phone. The device streams the content, not your phone. Your phone is more or less just a remote.

boy09 said:

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Cassius said:

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Why do these products, Chromecast, Roku, etc... require a connection to the internet if all I'm doing is using it to cast or mirror my screen?

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I know with the Chromecast, that's not how they work. It doesn't mirror your phone. The device streams the content, not your phone. Your phone is more or less just a remote.

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So it tells the device which URI to use and it connects and streams it?

How does authentication work?

Yes. With all the casting technologies what you are doing is effectively sending a notification to the receiving device that it needs to contact a server and request data. If the receiving device (AppleTV, Chromecast, Roku) does not have an internet connection you can't cast to the device, it doesn't use the internet from the casting device to download the data.

Not sure the USB-C to HDMI connection will work either, because a lot of these applications have usage limitations where it will block the output of the screen to the TV. Netflix will block the output of it's video to HDMI from an iPhone to a TV. Think it uses HDCP to determine whether it needs to be blocked or not, not 100% sure on that, and not 100% sure it still does this, it just did the last time I researched options.


Using your phone as a hotspot is the most straightforward way of accomplishing what you want to accomplish, if you have that service.