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URTWN(4) Device Drivers Manual URTWN(4)

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 spectrum only.

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 networks. 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 hostname.if(5).

The driver needs at least version 1.1p0 of the following firmware files, which are loaded when an interface is attached:


A prepackaged version of the firmware, designed to be used with pkg_add(1), can be found at:


The following adapters should work:

Airlink101 AWLL5088
Aus. Linx AL-9604R1S
B-Link BL-LW05-5R
Belkin F7D1102 Surf Wireless Micro
D-Link DWA-121
D-Link DWA-133
D-Link DWA-135
Digitus DN-7042
Edimax EW-7811Un
Full River FR-W100NUL
Hercules Wireless N USB Pico HWNUp-150
Netgear WNA1000A
Planex GW-USEco300
Planex GW-USNano2
Planex GW-USValue-EZ
Planex GW-USWExtreme
Sitecom WL-365
Solwise NET-WL-UMD-606N

The following hostname.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:
dhcp NONE NONE NONE 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 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 complete in time. The driver will reset the hardware. This should not happen.

arp(4), ifmedia(4), intro(4), netintro(4), usb(4), hostname.if(5), ifconfig(8)

The urtwn driver first appeared in OpenBSD 4.9.

The urtwn driver was written by Damien Bergamini ⟨damien@openbsd.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.
November 26, 2011 OpenBSD-5.1