OTUS(4) | Device Drivers Manual | OTUS(4)

# NAME

`otus` — Atheros USB IEEE 802.11a/b/g/n wireless network device

# SYNOPSIS

`otus* at uhub? port ?`

# DESCRIPTION

The `otus` driver supports USB 2.0 wireless network devices based on Atheros Communications AR9001U chipset.

The AR9001U chipset is made of an AR9170 MAC/Baseband and an AR9101 (1T2R), AR9102 (2T2R) or AR9104 (dual-band 2T2R) Radio.

These are the modes the `otus` 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 `otus` driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA1 and WPA2). WPA2 is currently the most secure encryption standard for wireless networks supported by OpenBSD. It is strongly recommended that neither WEP nor WPA1 are used as the sole mechanism to secure wireless communication, due to serious weaknesses. WPA1 is disabled by default and may be enabled using the option "`wpaprotos` wpa1,wpa2". For standard WPA networks which use pre-shared keys (PSK), keys are configured using the "`wpakey`" option. WPA-Enterprise networks require use of the wpa_supplicant package. "`wpaprotos` wpa1,wpa2". For standard WPA networks which use pre-shared keys (PSK), keys are configured using the "`wpakey`" option. WPA-Enterprise networks require use of the wpa_supplicant package.

The `otus` driver can be configured at runtime with ifconfig(8) or on boot with hostname.if(5).

# FILES

The driver needs at least version 1.0 of the following firmware files, which are loaded when an interface is attached:

/etc/firmware/otus-init
/etc/firmware/otus-main

Although these firmware files are freely redistributable, their usage is restricted. A prepackaged version of the firmware can be installed using fw_update(8).

# HARDWARE

The following adapters should work:

3Com 3CRUSBN275
Arcadyan WN7512
CACE AirPcap Nx
D-Link DWA-130 rev D1
D-Link DWA-160 rev A1
D-Link DWA-160 rev A2
IO-Data WN-GDN/US2
NEC Aterm WL300NU-G
Netgear WNDA3100
Netgear WN111 v2
Planex GW-US300
SMC Networks SMCWUSB-N2
TP-Link TL-WN821N v1, v2
Ubiquiti SR71 USB
Unex DNUA-81
Z-Com UB81
Z-Com UB82
ZyXEL NWD-271N

# EXAMPLES

The following example scans for available networks:

`# ifconfig otus0 scan`

The following hostname.if(5) example configures otus0 to join network “mynwid”, using WPA key “mywpakey”, obtaining an IP address using DHCP:

    join mynwid wpakey mywpakey
    inet autoconf

# DIAGNOSTICS

otus0: error N, could not read firmware ...
  For some reason, the driver was unable to read the microcode file from the filesystem. The file might be missing or corrupted.
otus0: 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.

# SEE ALSO

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

# HISTORY

The `otus` driver first appeared in OpenBSD 4.6.

# AUTHORS

The `otus` driver was written by Damien Bergamini <damien.bergamini@free.fr> based on source code licensed under the ISC released in 2008 by Atheros Communications for Linux.

# CAVEATS

The AVM FRITZ!WLAN USB Stick N adapter is currently not supported.

The `otus` driver does not support any of the 802.11n capabilities offered by the AR9001U chipset. Additional work is required in ieee80211(9) before those features can be supported.

March 27, 2025 | Debian