URTWN(4) BSD Kernel Interfaces Manual URTWN(4)
urtwn -- Realtek RTL8188CU/RTL8192CU USB IEEE 802.11b/g/n wireless network device
urtwn* at uhub? port ?
The urtwn driver supports USB 2.0 wireless network devices based on Realtek RTL8188CUS,
RTL8188CE-VAU, RTL8188RU and RTL8192CU chipsets.
The RTL8188CUS is a highly integrated 802.11n adapter that combines a MAC, a 1T1R capable
baseband and an RF in a single chip. It operates in the 2GHz spectrum only. The RTL8188RU
is a high-power variant of the RTL8188CUS. The RTL8188CE-VAU is a PCI Express Mini Card
adapter that attaches to the USB interface.
The RTL8192CU is a highly integrated multiple-in, multiple-out (MIMO) 802.11n adapter that
combines a MAC, a 2T2R capable baseband and an RF in a single chip. It operates in the 2GHz
These are the modes the urtwn driver can operate in:
BSS mode Also known as infrastructure mode, this is used when associating with an
access point, through which all traffic passes. This mode is the default.
monitor mode In this mode the driver is able to receive packets without associating with
an access point. This disables the internal receive filter and enables the
card to capture packets from networks which it wouldn't normally have access
to, or to scan for access points.
The urtwn driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected
Access (WPA-PSK and WPA2-PSK). WPA is the de facto encryption standard for wireless net-
works. It is strongly recommended that WEP not be used as the sole mechanism to secure
wireless communication, due to serious weaknesses in it.
The urtwn driver can be configured at runtime with ifconfig(8) or on boot with
The driver needs the following firmware files, which are loaded when an interface is
The following adapters should work:
Aus. Linx AL-9604R1S
Belkin F7D1102 Surf Wireless Micro
Full River FR-W100NUL
Hercules Wireless N USB Pico HWNUp-150
The following ifconfig.if(5) example configures urtwn0 to join whatever network is available
on boot, using WEP key ``0x1deadbeef1'', channel 11, obtaining an IP address using DHCP:
nwkey 0x1deadbeef1 chan 11
Configure urtwn0 to join network ``my_net'' using WPA with passphrase ``my_passphrase'':
# ifconfig urtwn0 nwid my_net wpakey my_passphrase
Join an existing BSS network, ``my_net'':
# ifconfig urtwn0 192.168.1.1 netmask 0xffffff00 nwid my_net
urtwn%d: error %d, could not read firmware %s For some reason, the driver was unable to
read the microcode file from the filesystem. The file might be missing or corrupted.
urtwn%d: device timeout A frame dispatched to the hardware for transmission did not com-
plete in time. The driver will reset the hardware. This should not happen.
arp(4), netintro(4), usb(4), ifconfig.if(5), wpa_supplicant.conf(5), ifconfig(8),
The urtwn device driver first appeared in OpenBSD 4.9 and in NetBSD 7.0.
The urtwn driver was written by Damien Bergamini <email@example.com> for OpenBSD and ported
to NetBSD by
NONAKA Kimihiro <firstname.lastname@example.org>.
The urtwn driver does not support any of the 802.11n capabilities offered by the adapters.
Additional work is required in ieee80211(9) before those features can be supported.
BSD June 13, 2012 BSD