首先查看usb设备

    pi@raspi ~ $ lsusb
    Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
    Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
    Bus 001 Device 004: ID 0ace:1215 ZyDAS ZD1211B 802.11g

注意，最后一行为无线网卡信息

打开https://wiki.debian.org/WiFi，查看是否有对照型号的固件

安装对应的固件

    pi@raspi ~ $ sudo apt-get install zd1211-firmware

完成后使用iwconfig检查是否已经安装成功

    pi@raspi ~ $ iwconfig
    wlan0     IEEE 802.11bg  ESSID:off/any
              Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm
              Retry  long limit:7   RTS thr:off   Fragment thr:off
              Power Management:off

    lo        no wireless extensions.
    
    eth0      no wireless extensions.