Black Box IC165AE manual Power Controls

CHAPTER 3: Installation

3.4 Power Controls

When the hub is connected to the USB connection, it initially draws less than 1⁄10 of an amp from the host connection. Each port is enabled one at a time. Initially, all attached devices are only allowed to draw 1⁄10 amp or less each.

When the hub is identified, it tells the host whether it is bus-powered or self-powered. If the hub is bus-powered, the device driver should only allow low-power devices to be enabled. If the hub is self-powered, the device driver can allow low-power and/or high-power devices to be attached.

NOTE

Early device drivers may not enforce these power limits. However, the USB Director/4-Port Hub is designed to automatically protect the host connection and the hub itself from overcurrent conditions if they exist.

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