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PGT(4) Device Drivers Manual PGT(4)

Conexant/Intersil Prism GT Full-MAC IEEE 802.11a/b/g wireless network device

pgt* at cardbus?
pgt* at pci?

The pgt driver provides support for Conexant/Intersil GT-series devices which can support the Full-Mac firmwares, using the ISL3877, ISL3880, and ISL3890 chips. The pgt driver will not (yet) work on similar devices using the ISL3886 or similar chips which use the Soft-Mac firmwares.

These are the modes the pgt 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 pgt driver can be configured to use hardware 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 pgt driver can be configured at runtime with ifconfig(8) or on boot with hostname.if(5).

The driver needs a set of firmware files which are loaded when an interface is brought up:


These firmware files are not free because Conexant refuses to grant distribution rights. In fact they have rebuffed thousands of attempts to start a dialogue on this issue. As a result, even though OpenBSD includes the driver, the firmware files cannot be included and users have to download these files on their own.

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


The following cards are among those supported by the pgt driver:
Card Chip Bus
3COM 3CRWE154G72 ISL3880 CardBus
D-Link DWL-g650 A1 ISL3890 PCI
I-O Data WN-G54/CB ISL3890 PCI
I4 Z-Com XG-600 ISL3890 PCI
I4 Z-Com XG-900 ISL3890 PCI
Intersil PRISM Indigo ISL3877 PCI
Intersil PRISM Duette ISL3890 PCI
NETGEAR WG511 (Taiwanese, not Chinese) ISL3890 CardBus
SMC EZ Connect g 2.4GHz SMC2802W ISL3890 PCI
SMC EZ Connect g 2.4GHz SMC2835W-v2 ISL3890 CardBus
SMC 2802Wv2 ISL3890 PCI
Soyo Aerielink ISL3890 CardBus
ZyXEL ZyAIR G-100 ISL3890 CardBus

The following hostname.if(5) example configures pgt0 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

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

inet NONE media autoselect \
	mediaopt hostap nwid my_net chan 11

Configure pgt0 for WEP, using hex key “0x1deadbeef1”:

# ifconfig pgt0 nwkey 0x1deadbeef1

Return pgt0 to its default settings:

# ifconfig pgt0 -bssid -chan media autoselect \
	nwid "" -nwkey

Join an existing BSS network, “my_net”:

# ifconfig pgt0 netmask 0xffffff00 nwid my_net

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

The pgt driver first appeared in OpenBSD 4.0.

The pgt driver was originally written for FreeBSD by Brian Fundakowski, and then rewritten for OpenBSD by Marcus Glocker and Claudio Jeker.

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).
September 3, 2011 OpenBSD-5.1