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Posted 30 July 2009 - 01:11 PM
USB signals are transmitted on a braided pair data cable with 90Ω ±15% impedance, labeled D+ and D−. Prior to USB 3.0, These collectively use half-duplex differential signaling to reduce the effects of electromagnetic noise on longer lines. Transmitted signal levels are 0.0–0.3 volts for low and 2.8–3.6 volts for high in full speed (FS) and low speed (LS) modes, and −10–10 mV for low and 360–440 mV for high in hi-speed (HS) mode. In FS mode the cable wires are not terminated, but the HS mode has termination of 45Ω to ground, or 90Ω differential to match the data cable impedance, reducing interference of particular kinds. USB 3.0 introduces two additional pairs of shielded twisted wire and new, mostly interoperable contacts in USB 3.0 cables, for them. They permit the higher data rate, and full duplex operation.
Posted 30 July 2009 - 01:38 PM
Posted 31 July 2009 - 01:56 AM
Posted 31 July 2009 - 12:06 PM
Umm, what? Using a 3.0 device, connecting with a 3.0 cable to a 3.0 port yields 2.0 speeds... I think there's a miscommunication here.
It won't do jack squat. You'll still be limited to USB2.0 speeds, even if it is a 3.0 device using a 3.0 cable.
Posted 31 July 2009 - 10:04 PM
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