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USB (a relatively novel rectangular connector) is physically identical to PS/2 (a historically standard round mini DIN connector)? This sort of reasoning is com

USB (a relatively novel rectangular connector) is physically identical to PS/2 (a historically standard round mini DIN connector)? This sort of reasoning is completely alien to me, which is probably why I'll never be as rich as Jobs.

MBCook 13y ago
USB connectors don't have any intelligence, they're just a way to connect a few wires together. In that sense, they work exactly like PS/2, AT keyboard connectors, Atari 2600 joysticks, and headphones. The only differences are the shapes and locations of the individual connections. The lightning connector isn't passive, it contains some active circuitry, so it's not nearly as simple. Edit: seems I misread the meaning.
- davepage 13y ago
  A physical connector has an electro-mechanical function, and the PHY layer has an electronic function. Regardless the technology, both are always required. So, lightning located some (small) part of the PHY in the connector rather than in the client or host (where it would likely be cheaper). Apple could have merely cross-wired the pins on each side of the connector to achieve a reversible design and thus eliminated this excess complexity. I suspect the design is motivated by IP/counterfeit protection. I do not believe any of that benefits the end user at all.
jfb 13y ago
Right, that was confusing. What I was trying to say is that USB was an improvement on PS2, where the mouse and keyboard ports were identical to the user.
deleted 13y ago
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mercutio2 13y ago
That's how I read that sentence the first time, too, but you can parse that sentence so it's true: Two USB ports which are electrically identical are superior to two PS/2 ports, one for keyboard and one for mouse, which are electrically different.
- Gormo 13y ago
  IIRC, PS/2 mouse and keyboard ports are electrically identical, and the reason that they can't be used interchangeably is that addressing for PS/2 devices is hardcoded at the software level, i.e. the BIOS always expects a keyboard connected to a specific port and a mouse connected to the other.

MBCook 13y ago

USB connectors don't have any intelligence, they're just a way to connect a few wires together. In that sense, they work exactly like PS/2, AT keyboard connectors, Atari 2600 joysticks, and headphones. The only differences are the shapes and locations of the individual connections. The lightning connector isn't passive, it contains some active circuitry, so it's not nearly as simple. Edit: seems I misread the meaning.

davepage 13y ago
A physical connector has an electro-mechanical function, and the PHY layer has an electronic function. Regardless the technology, both are always required. So, lightning located some (small) part of the PHY in the connector rather than in the client or host (where it would likely be cheaper). Apple could have merely cross-wired the pins on each side of the connector to achieve a reversible design and thus eliminated this excess complexity. I suspect the design is motivated by IP/counterfeit protection. I do not believe any of that benefits the end user at all.

jfb 13y ago

Right, that was confusing. What I was trying to say is that USB was an improvement on PS2, where the mouse and keyboard ports were identical to the user.

deleted 13y ago

[deleted]

mercutio2 13y ago

That's how I read that sentence the first time, too, but you can parse that sentence so it's true: Two USB ports which are electrically identical are superior to two PS/2 ports, one for keyboard and one for mouse, which are electrically different.

Gormo 13y ago
IIRC, PS/2 mouse and keyboard ports are electrically identical, and the reason that they can't be used interchangeably is that addressing for PS/2 devices is hardcoded at the software level, i.e. the BIOS always expects a keyboard connected to a specific port and a mouse connected to the other.