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Always found it a bit strange that USB-C is referred to as a "new connector" when it clearly seems to be an entirely new protocol. (Unlike the previous new conn

by xg15 3mo ago

Always found it a bit strange that USB-C is referred to as a "new connector" when it clearly seems to be an entirely new protocol. (Unlike the previous new connectors mini and micro which were just differently-shaped plugs for the same wires) So is the protocol technically USB 4.0 and USB-C "just" a new connector role defined by that protocol, or did they ditch the versioning and "USB-C" is its own thing? The guide mentions that USB 4.0 is the first version to require a USB-C connector, but then later refers to the "USB-C protocol". Is that the same as USB 4.0?

samatman 3mo ago
Perhaps you will find page 27, "USB signals over USB Type-C®", clears up the strangeness. At least when you get to the first section, "USB 2.0 Signaling Over Type-C".
ianburrell 3mo ago
USB-C is a connector. Part of the confusion is that USB specification versions have come to be associated with the protocols and speeds defined there. The basic division is between USB2 and USB3 which are separate protocols on different wires. USB-C has multiple high speed lanes. USB 3.0 defined the SuperSpeed protocol and 5GBps speed. Later versions increased speeds, 10GBps (USB3.1), 20GBps (USB3.2). These were also called Gen1, Gen2, or now just the speeds. Then, there are alternate modes which run other protocols over high speed lanes. DisplayPort is the most common one. Next, USB4 defined USB4 protocol which multiplexes SuperSpeed and DisplayPort over two high speed lanes. USB4 requires USB-C. This is basically Thunderbolt standardized. Specification also defines 20Gbps, 40Gbps, and 80Gbps speeds.
rjh29 3mo ago
It's easier to split USB 3 into two stages: 1) USB 2.0 - 480 Mbps, 0.5A (2.5W / 5V) 2) USB 3.0 on Type-A - increases data to 5/10 Gbps (e.g. for SSDs) and power to 0.9A (4.5W / 5V). 3) USB 3.0 on Type-C - adds pins to enable most of the new stuff: base 3A (15W / 5V) and up to 240W with power delivery; extra data lanes for 20 Gbps, DisplayPort for external monitors. 4) USB 4.0 on Type-C - changes protocol completely (using packets instead of fixed lanes per pin) and requires minimum speeds and the use of type-C port. A-to-C cables act like A-to-A as they don't have extra pins - they're just easier to use. Pre-Power Delivery lots of phone chargers used A-to-C cables with a custom protocol to negotiate power draw beyond 0.9A. And some devices pull 3A anyway just assuming there's a power brick that supports 3A attached. But technically none of that is compliant.

by xg15 3mo ago

samatman 3mo ago

Perhaps you will find page 27, "USB signals over USB Type-C®", clears up the strangeness. At least when you get to the first section, "USB 2.0 Signaling Over Type-C".

ianburrell 3mo ago

USB-C is a connector. Part of the confusion is that USB specification versions have come to be associated with the protocols and speeds defined there. The basic division is between USB2 and USB3 which are separate protocols on different wires. USB-C has multiple high speed lanes. USB 3.0 defined the SuperSpeed protocol and 5GBps speed. Later versions increased speeds, 10GBps (USB3.1), 20GBps (USB3.2). These were also called Gen1, Gen2, or now just the speeds. Then, there are alternate modes which run other protocols over high speed lanes. DisplayPort is the most common one. Next, USB4 defined USB4 protocol which multiplexes SuperSpeed and DisplayPort over two high speed lanes. USB4 requires USB-C. This is basically Thunderbolt standardized. Specification also defines 20Gbps, 40Gbps, and 80Gbps speeds.

rjh29 3mo ago

It's easier to split USB 3 into two stages: 1) USB 2.0 - 480 Mbps, 0.5A (2.5W / 5V) 2) USB 3.0 on Type-A - increases data to 5/10 Gbps (e.g. for SSDs) and power to 0.9A (4.5W / 5V). 3) USB 3.0 on Type-C - adds pins to enable most of the new stuff: base 3A (15W / 5V) and up to 240W with power delivery; extra data lanes for 20 Gbps, DisplayPort for external monitors. 4) USB 4.0 on Type-C - changes protocol completely (using packets instead of fixed lanes per pin) and requires minimum speeds and the use of type-C port. A-to-C cables act like A-to-A as they don't have extra pins - they're just easier to use. Pre-Power Delivery lots of phone chargers used A-to-C cables with a custom protocol to negotiate power draw beyond 0.9A. And some devices pull 3A anyway just assuming there's a power brick that supports 3A attached. But technically none of that is compliant.