A question about USB-C

[Chiru]

i was wondering, if USB type-C has 24 pins and USB type-A has 4 and a cable has on one side USB type-A and on the other end USB type-C connector. That would mean that 20 pins are not connected to any conductors, just like placeholders, right?

 

That means if you would solder the 4 USB-A conductors directly on the PCB of the device with a USB-C connector, the device would work anyway and therefore the other 20 pins are basically inactive/useless?

 

Am i correct?

[badreg]

USB 3.0 Type A has nine pins. Four are for backwards compatibility with USB 2.0 and 1.0.

 

USB Type C has 24 pins, but only four are used in a USB 2.0 cable. The remaining 20 pins are for USB 3.0, but these pins are doubled so that the connector can be flipped. There are nine active pins, like Type A, plus one for detecting the plug orientation.

 

[Moonzy]

13 minutes ago, Chiru said:

Am i correct?

yes*

 

*depends if the type C device is designed to operate on USB 2.0 protocol

 

more in-depth analysis

Spoiler

 

as you can see from the picture, USB Type C have more channels for data (thus the higher bandwidth, if device utilises those channels)

some devices are backwards compatible, meaning they can function using only D+ and D- pins, and increase the number of pins used when available for more bandwidth

a lot of the Type-C pin are replicated to allow the function of upside down operation, so not all 24 pins are unique

 

[Chiru]

13 minutes ago, Moonzy said:

yes*

 

*depends if the type C device is designed to operate on USB 2.0 protocol

 

more in-depth analysis

  Hide contents

 

as you can see from the picture, USB Type C have more channels for data (thus the higher bandwidth, if device utilises those channels)

some devices are backwards compatible, meaning they can function using only D+ and D- pins, and increase the number of pins used when available for more bandwidth

a lot of the Type-C pin are replicated to allow the function of upside down operation, so not all 24 pins are unique

 

But a USB 3.0 cable has 4 or 5 conductors?

[Moonzy]

3 minutes ago, Chiru said:

But a USB 3.0 cable has 4 or 5 conductors?

a USB 3.0 cable have 9 connectors.

Spoiler

the front row (4 connector laying flat towards us) is usb 2.0 connection

the back row (5 pins) is the extra pins to increase bandwidth

 

all 9 pins have to be used to be considered a 3.0 connection

[Chiru]

but a usb 3.0 cable doesnt have 9 wires inside

[Moonzy]

Just now, Chiru said:

but a usb 3.0 cable doesnt have 9 wires inside

there are two GND pins, they might both share a single cable

if there are less than 8 cables, my life is a lie