Operation Manual

Figure 1-8: Two USB wireless adapters, suitable for use with the Raspberry Pi
Using such a device, the Pi can connect to a wide range of wireless networks, including those running on the latest 802.11n high-
speed standard. Before purchasing a USB wireless adapter, check the following:
• Ensure that Linux is listed as a supported operating system. Some wireless adapters are provided with drivers for Windows
and OS X only, making them incompatible with the Raspberry Pi. A list of Wi-Fi adapters known to work with the
Raspberry Pi can be found on the following website:
http://elinux.org/RPi_VerifiedPeripherals#USB_WiFi_Adapters
• Ensure that your Wi-Fi network type is supported by the USB wireless adapter. The network type will be listed in the
specifications as a number followed by a letter. If your network type is 802.11a, for example, an 802.11g wireless adapter
won’t work.
• Check the frequencies supported by the card. Some wireless network standards, like 802.11a, support more than one
frequency. If a USB wireless adapter is designed to work on a 2.4GHz network, it won’t connect to a 5GHz network.
• Check the encryption type used by your wireless network. Most modern USB wireless adapters support all forms of
encryption, but if you’re buying a second-hand or older model, you may find it won’t connect to your network. Common
encryption types include the outdated WEP and more modern WPA and WPA2.
Configuration of the wireless connection is done within Linux, so for now it’s enough to simply connect the adapter to the Pi
(ideally through a powered USB hub.) You’ll learn how to configure the connection in Chapter 4, “Network Configuration”.
Connecting Power
The Raspberry Pi is powered by the small micro-USB connector found on the lower left side of the circuit board. This connector
is the same as found on the majority of smartphones and some tablet devices.
Many chargers designed for smartphones will work with the Raspberry Pi, but not all. The Pi is more power-hungry than most
micro-USB devices, and requires up to 700mA in order to operate. Some chargers can only supply up to 500mA, causing
intermittent problems in the Pi’s operation (see Chapter 3, “Troubleshooting”).
Connecting the Pi to the USB port on a desktop or laptop computer is possible, but not recommended. As with smaller
chargers, the USB ports on a computer can’t provide the power required for the Pi to work properly.
Only connect the micro-USB power supply when you are ready to start using the Pi. With no power button on the device, it will
start working the instant power is connected and can only be turned off again by physically removing the power cable.