Display Port bandwidth over usb 3.1 type c

[ze_abreu]

Hi hope someone helps me understand how it is possible for usb 3.1 Type c wich has a bandwidth of 10 gbps being able to work has an displayport 1.4 connection wich has a bandwidth of 25,92 gbps or 2,5x the bandwith of usb 3.1.
Thank You

 

[Barty1884]

Type-C is just a connection standard, nothing more.
Technically, a Type-C connector could be used with USB1.1 speed limitations - of course, there's no reason for anybody to do that.

A type-C connector can be *just* a USB port (data transfer, power etc) OR can be Thunderbolt3, using the Type-C connector.
Most Type-C ports are also Thunderbolt3 enabled. Increasing that max to 40Gbit/s.

There;s also alternative modes (DP, HDMI etc in addition to TB).

USB 3.1 Gen1 has a max bandwidth of 5 Gbit/s
3.1 Gen2 is 10 Gbit/s
DP 1.4's max is 32.4 Gbit/s, although data transfer's max is 25.92 Gbit/s
TB3 is 40 Gbit/s

With a TB3 enabled Type-C, you can have the concurrent bandwidth of both DisplayPort1.4 AND USB3.1 Gen2 (25.92 + 10)

 

[InvalidError]

Technically, a Type-C connector could be used with USB1.1 speed limitations - of course, there's no reason for anybody to do that.

Type-C has wires dedicated to USB1.x/2.0 and many devices use exactly that, USB1.x/2.0 over type-C connectors and the cables they come with only provide the exact same USB 1.x/2.0 wiring you get from regular type-A/B/uB cables. Many modern low-end phones and tablets have USB2.0 Type-C. Keyboards and mice with modular cables are adopting Type-C as well despite operating at USB 1.1 speed (12Mbps) or less.

Why do they do it? Simple: the Type-C connector is cheaper than A/B. In some countries, it is also about to become required by law to reduce the amount of e-waste generated by proprietary connectors and incompatible standards.

 

[Barty1884]

I stand corrected IE.
I meant exclusively 1.1, not just as part of the overall package - but I guess on some KB/Ms, that's exactly what one end is.

 

[ze_abreu]

Thanks for the answer, i got that idea because in my monitor (LG 27UK850) it says that it has an USB type c connector maybe they shouldn t use that term usb because to work has a DP it could never work has an usb right? Shouldn t be stated only that it has a type c port? I was aware of thunderbolt type c wich is used also on my mac and in that case i got it because he as lot of bandwidht but in usb case..

 

[Barty1884]

Not 100% sure on the question.
As per the product spec page, the Type-C in this instance can operate in DP alternate mode:
Yes x1 (ver 3.1 - Gen1) PD 60W / DP Alternate Mode / Data

BUT, from reading it, it looks like the Type-C, when something else is being used for display purposes, can be used as a USB passthrough.
https://www.lg.com/us/monitors/lg-27UK850-W-4k-uhd-led-monitor

 

[ze_abreu]

I got also an official answer by vesa that i leave here for anyone who might have the same doubt.

DisplayPort is sent over Type-C via Alt Mode, where the four high-speed lanes in the Type-C are used for DisplayPort. If the source supports DisplayPort High Bit Rate 3 (often called DP 1.3 or 1.4), then it can send 8.1 Gbps over each lane for a maximum raw bandwidth 32 Gbps. Reduce that number by 20% for overhead.

In USB superspeed mode, the data rate is 10Gbps but not across four lanes.