CHAPTER 3
Devices and Ports
This chapter describes both the built-in I/O devices and the ports for connecting external I/O devices. Each of the following sections describes an I/O port or device.
USB Ports
The PowerBook G4 17-inch computer has two external USB v1.1 ports that can be used to connect additional I/O devices such as a USB mouse, printers, scanners, and low-speed storage devices.
The USB ports on the PowerBook G4 17-inch computer comply with the Universal Serial Bus Specification
1.1Final Draft Revision. For more information about USB on Macintosh computers, consult the references at “USB Interface” (page 62).
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(page 25) is an illustration of a Type A port and matching connector. Table 3-1 shows the pin assignments.
Figure 3-1USB Type A port
Table 3-1Pin assignments on the USB port
Pin | Signal name | Description |
1 | VCC | +5 VDC |
2 | D– | Data – |
3 | D+ | Data + |
4 | GND | Ground |
The 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 operation requires the use of shielded cables.
Legacy Document 2003-03-01 © 2003 Apple Computer, Inc. All Rights Reserved.
