Mac won’t recognize Samsung SMRT TV

HDMI 2.1 is a completely different protocol, electrically, than everything called HDMI that came before it.

if you don't need higher than 4K at 30 Hz, fall back to HDMI 2.0 and live happily ever after.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

<< because sometimes Macs will only recognize second displays when they are connected via USB-C. >>

That is not true. Check carefully that you are allowing the Mac to recognize the display, because as I said above, no internal settings can make the picture come on.

But HDMI has been pushed so hard that it is now unrecognizable from the friendly 'everything just works with everything' over its original environment of 720i TV sets.

you have at least two thought streams going here, and they are completely crossed up in my mind.

what problem are you now trying to solve?

your one computer with a nearby HDMI display, or

the gigantic two hops of fiber-optic with an adapter in between?

Modern Displays, including TV sets, with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays and TVs have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

Some displays and TVs include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own can generally not respond to the Mac's query, and will stay dark.

I dunno much, Alwaysbooks,,but i’d imagine for an HDMI run of that length, some kind of active adapter/hdmi amplifier/booster must be involved somehow… this company makes something like that… https://www.startech.com/en-ca/audio-video-products/st121hd20l and this one:

https://www.extron.com/HDMI-Distribution-Amplifiers/prodsubtype-504, maybe this ?

https://www.crestron.com/Products/Video/HDMI-Solutions/HDMI-Extenders/HD-EXT-USB-2000-C

i’m just guessing here , though

john b

I don't think you can stop in the middle at HDMI, the re-insert that HDMI into the second segment of Fiber-optic cable. Maybe you can add a fiber-optic to fiber optic repeater, if there is such a thing.

I think the tragic flaw may be trying to go onto a SECOND fiber optic. If it were all one fiber-optic cable, it would likely work fine. Better ask your expert.