2 ms·

Or just put + and - through a rectifier and you don't need an extra pin. Data lines -- use differential signalling and polarity determined by whether +/- got r

by dheera 3y ago

Or just put + and - through a rectifier and you don't need an extra pin. Data lines -- use differential signalling and polarity determined by whether +/- got reversed by the rectifier or not. Or do like Comcast does and put all bidirectional data through 1 conductor at multi-gigabit speeds.

crote 3y ago
How are you going to implement the rectifier, though? The usual implementation is using diodes, but that means you lose twice the diode forward voltage to the rectifier. Even with a Schottky diode that means you are losing 0.5V-1.0V. That's a 10%-20% loss at 5V! You could use a transistor-based "ideal diode" solution, but that's not going to be cheap - especially in the 90s.
- deleted 3y ago
  [deleted]
ilyt 3y ago
Maybe if you have no clue about electronics don't talk about electronics... > Or do like Comcast does and put all bidirectional data through 1 conductor at multi-gigabit speeds. And how much modem's transceiver cost ? And how does that compare to cost of computer mouse or other cheap USB peripherals.
- dheera 3y ago
  They'll cost 1/100 the price if every USB port in the world uses them. Auto parts for common models of cars are so incredibly cheap for a reason.
  - ilyt 3y ago
    USB1 was designed in times where transistors were significantly more expensive. And in times where laptops or phones or any other situation when you disconnected peripherals were far less common. Like, it still was improvement over PS/2. It's also not just few transistors to flip the lines around, it's also the logic to drive that
    - dheera 3y ago
      Y'all are talking as if you were in the vacuum tube era. There were 42 million transistors in a Pentium 4, I'm sure they could have put a few thousand per USB port if they thunk optimistically instead of pessimistically. When USB came out we already had some very crude 3D realtime rendering already at that time available to mass consumers, I'm sure we could have figured out how to flip power on a port if we put our minds to it. Think "how can we make shit happen" instead of excuses of why it's hard. It's by doing hard things that we got to the 80 billion transistors of modern GPUs.
      - ilyt 3y ago
        > There were 42 million transistors in a Pentium 4 USB 1.1 was in '96 That's Pentium 1 era. Pentium 2 was released year after. Pentium 1 had one tenth of that > When USB came out we already had some very crude 3D realtime rendering already at that time available to mass consumers, I'm sure we could have figured out how to flip power on a port if we put our minds to it. Why your six neuron brain can't imagine saving pennies on chips used in cheap computer peripherals?

by dheera 3y ago

crote 3y ago

How are you going to implement the rectifier, though? The usual implementation is using diodes, but that means you lose twice the diode forward voltage to the rectifier. Even with a Schottky diode that means you are losing 0.5V-1.0V. That's a 10%-20% loss at 5V! You could use a transistor-based "ideal diode" solution, but that's not going to be cheap - especially in the 90s.

deleted 3y ago
[deleted]

ilyt 3y ago

Maybe if you have no clue about electronics don't talk about electronics... > Or do like Comcast does and put all bidirectional data through 1 conductor at multi-gigabit speeds. And how much modem's transceiver cost ? And how does that compare to cost of computer mouse or other cheap USB peripherals.

dheera 3y ago
They'll cost 1/100 the price if every USB port in the world uses them. Auto parts for common models of cars are so incredibly cheap for a reason.
- ilyt 3y ago
  USB1 was designed in times where transistors were significantly more expensive. And in times where laptops or phones or any other situation when you disconnected peripherals were far less common. Like, it still was improvement over PS/2. It's also not just few transistors to flip the lines around, it's also the logic to drive that
  - dheera 3y ago
    Y'all are talking as if you were in the vacuum tube era. There were 42 million transistors in a Pentium 4, I'm sure they could have put a few thousand per USB port if they thunk optimistically instead of pessimistically. When USB came out we already had some very crude 3D realtime rendering already at that time available to mass consumers, I'm sure we could have figured out how to flip power on a port if we put our minds to it. Think "how can we make shit happen" instead of excuses of why it's hard. It's by doing hard things that we got to the 80 billion transistors of modern GPUs.
    - ilyt 3y ago
      > There were 42 million transistors in a Pentium 4 USB 1.1 was in '96 That's Pentium 1 era. Pentium 2 was released year after. Pentium 1 had one tenth of that > When USB came out we already had some very crude 3D realtime rendering already at that time available to mass consumers, I'm sure we could have figured out how to flip power on a port if we put our minds to it. Why your six neuron brain can't imagine saving pennies on chips used in cheap computer peripherals?