urtw —
Realtek RTL8187B/L USB IEEE 802.11b/g wireless network
  device
The urtw driver supports USB 802.11b/g wireless adapters
  based on the Realtek RTL8187B/L.
urtw supports
    station and monitor mode
    operation. Only one virtual interface may be configured at any time. For
    more information on configuring this device, see
    ifconfig(8).
The urtw driver supports Realtek RTL8187B/L based
  wireless network devices, including:
  
    | Card | Radio | Bus | 
  
    | Belkin F5D7050E | RTL8225 | USB | 
  
    | Linksys WUSB54GCv2 | RTL8225 | USB | 
  
    | Netgear WG111v2 | RTL8225 | USB | 
  
    | Netgear WG111v3 | RTL8225 | USB | 
  
    | Safehome WLG-1500SMA5 | RTL8225 | USB | 
  
    | Shuttle XPC Accessory PN20 | RTL8225 | USB | 
  
    | Sitecom WL168v1 | RTL8225 | USB | 
  
    | Sitecom WL168v4 | RTL8225 | USB | 
  
    | SureCom EP-9001-g(2A) | RTL8225 | USB | 
  
    | TRENDnet TEW-424UB V3.xR | RTL8225 | USB | 
ifconfig.if(5) example
  configures urtw0 to join whatever network is available on boot, using WEP key
  “0x1deadbeef1”, channel 11, obtaining an IP address using DHCP:
nwkey 0x1deadbeef1 chan 11
dhcp
 
Join an existing BSS network, “my_net”:
# ifconfig urtw0 192.168.1.1 netmask 0xffffff00 nwid my_net
 
The urtw device driver first appeared in
  FreeBSD 8.0 and NetBSD 6.0.
The urtw driver was written by Weongyo
  Jeong ⟨weongyo@FreeBSD.org⟩.