OTUS(4)

💖 OTUS(4) — the Atheros AR9170 USB IEEE 802.11a/b/g/n wireless network device, bestie 💖

okay so. you found a wifi stick with an Atheros AR9170 chipset in it and now you need to know what otus actually does. this is the kernel interfaces manual page for it, and yes i am going to walk you through every single line because you deserve to know. 🦋

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✨ NAME ✨

otus — Atheros AR9170 USB IEEE 802.11a/b/g/n wireless network device

like. that's the whole vibe. it's a driver for a USB wifi thing. 💅

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✨ SYNOPSIS ✨

so if you want to bake this driver directly into your kernel (main character energy, honestly), you drop these lines into your kernel configuration file:

device ehci
device uhci
device ohci
device usb
device otus
device wlan

OR — and this is the lowkey easier route — you can load it as a module at boot time instead, by putting this one singular line into loader.conf(5):

if_otus_load="YES"

that's it. that's the whole synopsis. slay. ✨

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✨ DESCRIPTION ✨

okay so here's the tea. 🍓

the otus driver supports USB 2.0 wireless network devices based on the Atheros AR9170 chipset.

the Atheros AR9170 is a draft-802.11n adapter that uses an external radio to operate in either 2.4GHz only, or 2.4GHz and 5GHz.

now the radios, because there's three of them and they are NOT the same:

• The AR9101 radio supports 1T1R operation in 2GHz only.
• The AR9102 radio supports 2T2R operation in 2GHz only.
• The AR9104 radio supports 2T2R operation both 2GHz and 5GHz.

so like, check which radio you got before you get your hopes up about 5GHz, iykyk. 🙈

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🌈 the modes it can run in 🌈

these are the modes the otus driver can operate in:

• BSS mode — also known as infrastructure mode. this is the one you use when you're associating with an access point, and all your traffic passes through that AP. this mode is the default. 👑

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🔐 encryption 🔐

the otus 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, periodt.

okay but listen. it is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, because of serious weaknesses in it. like, seriously. WEP is giving "i left the front door open on purpose." do not. 💀

you can configure the otus driver at runtime with ifconfig(8). 🫶

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✨ FILES ✨

the driver needs at least version 1.0 of the following firmware files, and they get loaded when an interface is attached:

/boot/kernel/otusfw-init.ko
/boot/kernel/otusfw-main.ko

no firmware, no wifi. it's giving "bring your own brain." 🧚

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✨ HARDWARE ✨

the otus driver provides support for Atheros AR9170 USB IEEE 802.11b/g/n wireless network adapters, including these absolute icons:

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

if your dongle is on this list, congrats, you ate. 🔥

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✨ EXAMPLES ✨

okay bestie, here's how you actually use it. 💜

Join an existing BSS network (i.e., connect to an access point):

ifconfig wlan create wlandev otus0 inet 192.168.0.20 \
    netmask 0xffffff00

Join a specific BSS network with network name “my_net”:

ifconfig wlan create wlandev otus0 ssid my_net up

Join a specific BSS network with 64-bit WEP encryption:

ifconfig wlan create wlandev otus0 ssid my_net \
        wepmode on wepkey 0x1234567890 weptxkey 1 up

(remember what we said about WEP though. 👀)

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✨ DIAGNOSTICS ✨

• %s: failed load firmware of file otusfw-main — for some reason, the driver was unable to read the microcode file from the filesystem. the file might be missing or corrupted. 😭

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✨ SEE ALSO ✨

intro(1), netintro(4), otusfw(4), usb(4), wlan(4), arp(8), hostapd(8), ifconfig(8), wpa_supplicant(8)

go read those too. they're the group chat. 🌸

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✨ HISTORY ✨

the otus driver first appeared in OpenBSD 4.6. vintage, honestly. ⭐

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✨ AUTHORS ✨

the otus driver was written by Damien Bergamini <damien@openbsd.org> and ported by Adrian Chadd <adrian@freebsd.org>.

thank you kings. 👑🫶

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✨ CAVEATS ✨

okay so the big one: the otus driver only supports 802.11a/b/g operations. 802.11n operation is not supported at this time.

so yeah. it says draft-802.11n up top but do not come for me about 802.11n, because n is not happening right now. that's the whole caveat. no cap. 💅

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and that's the page, bestie!! this was the Debian build of the otus(4) kernel interfaces manual, dated September 25, 2015 — like, a whole era ago, but the wifi lore is forever. go forth and connect responsibly. 🌈✨💖