RTW(4) | Device Drivers Manual | RTW(4)

# NAME

`rtw` — Realtek RTL8180L IEEE 802.11b wireless network device

# SYNOPSIS

`rtw* at cardbus?`
`rtw* at pci?`

# DESCRIPTION

The `rtw` driver supports PCI/CardBus 802.11b wireless adapters based on the Realtek RTL8180L.

A variety of radio transceivers can be found in these devices, including the Philips SA2400A, Maxim MAX2820, and GCT GRF5101.

These are the modes the `rtw` 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.
IBSS mode
  Also known as IEEE ad-hoc mode or peer-to-peer mode. This is the standardized method of operating without an access point. Stations associate with a service set. However, actual connections between stations are peer-to-peer.
Host AP
  In this mode the driver acts as an access point (base station) for other cards.
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 `rtw` driver can be configured to use software Wired Equivalent Privacy (WEP). It is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, due to serious weaknesses in it.

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

# HARDWARE

The following adapters should work:

Card | Radio | Bus
`Allnet ALL0182` | SA2400 | CardBus
`Belkin F5D6020 V3` | SA2400 | CardBus
`Buffalo WLI-CB-B11` | SA2400 | CardBus
`Corega CG-WLCB11V3` | SA2400 | CardBus
`D-Link DWL-610` | ? | CardBus
`Edimax EW-7106` | SA2400 | CardBus
`GigaFast WF721-AEX (R* serial)` | GRF5101 | CardBus
`Jensen AirLink 6011` | GRF5101 | CardBus
`Level-One WPC-0101` | SA2400 | CardBus
`Linksys WPC11 v4` | MAX2820 | CardBus
`Netgear MA521` | SA2400 | CardBus
`Ovislink AirLive WL-1120PCM` | SA2400 | CardBus
`Planet WL-3553` | SA2400 | CardBus
`Q-Tec 770WC` | SA2400 | CardBus
`Q-Tec 775WC` | SA2400 | CardBus
`Roper FreeLan 802.11b` | SA2400 | CardBus
`SAFECOM SWLCR-1100` | SA2400 | CardBus
`TRENDnet TEW-226PC` | ? | CardBus
`VCTnet PC-11B1` | SA2400 | CardBus
`Winstron CB-200B` | SA2400 | CardBus
`Zonet ZEW1000` | GRF5101 | CardBus

# EXAMPLES

The following example scans for available networks:

`# ifconfig rtw0 scan`

The following hostname.if(5) example configures rtw0 to join network “mynwid”, using WEP key “mywepkey”, obtaining an IP address using DHCP:

    nwid mynwid nwkey mywepkey
    inet autoconf

The following hostname.if(5) example creates a host-based access point on boot:

    mediaopt hostap
    nwid mynwid nwkey mywepkey
    inet 192.168.1.1 255.255.255.0

# SEE ALSO

arp(4), cardbus(4), ifmedia(4), intro(4), netintro(4), pci(4), hostname.if(5), hostapd(8), ifconfig(8)

Realtek, https://www.realtek.com/en.

# HISTORY

The `rtw` device driver first appeared in OpenBSD 3.7.

# AUTHORS

The `rtw` driver was written by David Young <dyoung@NetBSD.org> and ported to OpenBSD by Jonathan Gray <jsg@openbsd.org>.

# CAVEATS

GCT refuse to release any documentation on their GRF5101 RF transceiver.

While PCI devices will attach, most of them are not able to transmit.

Host AP mode doesn't support power saving. Clients attempting to use power saving mode may experience significant packet loss (disabling power saving on the client will fix this).

March 27, 2025 | Debian