Operation Manual

Then test the settings by either opening a web browser or using the following ping command (see Figure 4-2):
ping -c 1 www.raspberrypi.org
Figure 4-2: A successful test of networking on the Raspberry Pi Model B
Wireless Networking
Although no current models of the Raspberry Pi include Wi-Fi networking hardware onboard, it’s possible to add wireless
connectivity with a simple USB Wi-Fi adapter. However, you will need to configure the adapter before you can use it to get your
Pi online.
USB Wi-Fi adapters are very power-hungry. If you connect one directly to the Pi’s USB port, the chances are it simply won’t work. Instead, connect a
powered USB hub to the Pi, and then insert the Wi-Fi adapter into that.
Before you start to set up the wireless interface, you’ll need to know the Service Set Identifier (SSID)—also known as the
network name—of the wireless router to which you want to connect, along with the type of encryption in use and the password
required. You’ll also need to know what type of wireless network it is. A USB adapter designed for 802.11a Wi-Fi may not
connect to an 802.11g network, and vice versa.
In order for the USB wireless adapter to be addressed by the system, a software bundle known as a firmware is required. While
some distributions include a selection of the most common Wi-Fi firmware installed by default, others do not. At present, to save
space, most distributions designed for the Raspberry Pi need the firmware files for a wireless card installing manually.
This, unfortunately, can lead to a Catch-22 situation: in order to download the firmware files, the Pi must be connected to the
Internet. If you can spare a wired port on your router or gateway for a few minutes, that’s not a problem. However, if wireless is
your only way of getting online, you’ll need to manually download the firmware installation package on a different computer, and
then transfer it across to the Pi by either copying it to the Pi’s SD card or connecting an external storage device such as a USB
flash drive.
To find the correct firmware file to download, you’ll need to know what type of wireless adapter you have. Although various
companies sell branded USB wireless adapters, the number of companies that actually manufacture the components is a lot
smaller. Several different manufacturers may use the same type of chip inside their USB wireless adapters, making them all
compatible with the same firmware. As a result, the labelling on a device or its packaging is not enough to know which firmware
you should install. Instead, you’ll need to connect the device to the Pi and check the kernel ring buffer for error messages. If
you’ve already connected the wireless adapter as instructed in Chapter 1, “Meet the Raspberry Pi”, you can continue. If not,
connect the adapter now.