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USB Connectors

The USB ports use USB Type A connectors, which have four pins each. Two of the pins are used for power and two for data. Figure 3-1 is an illustration of a Type A port and matching connector. Table 3-1 shows the pin assignments.

Figure 3-1 USB Type A port and connector



Table 3-1 Pin assignments on the USB port


Pin

Signal name

Description

1 VCC +5 VDC
2 D- Data -
3 D+ Data +
4 GND Ground

The iMac computer provides 5-volt power at 500 mA for each of the two ports.

The USB ports support both low-speed and high-speed data transfers, at up to 1.5 Mbits per second and 12 Mbits per second, respectively. High-speed operations requires the use of shielded cables.


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