iPhone 15 & iPhone 15 Pro can connect to an external 4K display without dongles

AppleInsider

Apple's tech specs for both the iPhone 15 and the iPhone 15 Pro have revealed that an adapter is no longer required to connect the devices to a monitor -- and that monitor can display up to 4K HDR at 60Hz.

USB-C on iPhone

Previously, connecting a monitor to an iPhone required a Lightning to HDMI adapter of some sort, and was limited to 1080P video, or AirPlay to a compatible device in some cases. The addition of USB-C to both units has upgraded this compatibility greatly.

Given the nature of the DisplayPort alt mode embedded in USB-C, it's likely that a USB-C to HDMI cable will work, and so will a USB-C to USB-C cable, as work on a USB-C iPad Pro now.

Apple spells out what the device can do, including this capability, on the iPhone 15 tech specs page. And, as MacRumors noted in their discovery of the feature late on Thursday, it's also possible to use Apple's USB-C Digital AV Multiport Adapter for 40K/60 on HDMI, but without HDR.

iPhone USB-C data speeds have no bearing on USB-C DisplayMode alt mode capabilities

It's beyond the scope of this article to discuss how USB-C channel allocation works, and the differences between the A16 Bionic and the A17 Pro have led to USB 2.0 raw data speeds at the lower end, yet enough speed for 4K60 video on both.

In short, the A16 chip does not have USB 3 support natively on the chipset. The fourth generation iPad Air that could reach those transfer speeds had a discrete USB controller off the die, and only the "X" A-series processors had closer to USB 3 data speeds. It appears that the A17 Pro chip also has full USB 3 support with DisplayMode alt mode implementation.

Apple seems to have chosen to allocate fixed bandwidth to this video feature in the iPhone 15 on USB-C. It also appears to use USB-C timing and dynamic pin data allocation to distribute bandwidth as necessary on the iPhone 15 Pro.

Presumably, this feature will work with USB-C docks the same as it does on the iPad with the iPhone 15 Pro, minus Stage Manager which is not supported on iOS 17, but is on iPadOS 17. It's not clear if docks will work the same on the iPhone 15 yet given the USB 2.0 data rate on the lower-end device, and only actual testing will tell.

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kmarei

Oh the horror!
maybe switching to usb-c wasn't such a bad idea after all
thanks EU

dhawkins541

 Apple switching to usb c this year allows them to lock in a year of higher transfer speeds for pro devices and then it will likely trickle down to the cheaper devices next year. 

freeassociate2

kmarei said:

Oh the horror!
maybe switching to usb-c wasn't such a bad idea after all
thanks EU

Or maybe just admit that it’s a mixed bag for a lot of reasons, and that perhaps the EU’s meddling didn’t significantly impact Apple’s design pipeline (seeing as how the lead time on on-die features is years long).

But by all means, toot that little horn like you actually know what went on in development and management.

cornelius1

dhawkins541 said:

 Apple switching to usb c this year allows them to lock in a year of higher transfer speeds for pro devices and then it will likely trickle down to the cheaper devices next year. 

Ideally, but not necessarily, since naming iPhone 15 Pro's chip as "A17 Pro" most likely implies there will be a non-pro version of A17, and that might be used in iPhone 16 and exclude the USB 3 controller that is required for the higher transfer speeds.

godofbiscuits

kmarei said:

Oh the horror!
maybe switching to usb-c wasn't such a bad idea after all
Thanks EU

Don't give them too much credit.  The EU only specified USBC as a connector , and that for power/charging purposes.