The wifi card does not work out of the box. Pay attention to the revision number of the wifi card. The revision 02 does not work while the revision 01 of the same model should work (as indicated in this tutorial).

rsandu: I may confirm that revision 01 does work out of the box (on a Dell Inspiron 1520 PP22L). Test was made on Trisquel 5.0 (LiveCD), kernel 2.6.38-11-generic.

lammi87: Tested revision 01 on Acer TravelMate 7520 and it worked out of the box.

lspci -vmmnn (revision 01)

Slot:	05:00.0
Class:	Network controller [0280]
Vendor:	Broadcom Corporation [14e4]
Device:	BCM4311 802.11b/g WLAN [4311]
SVendor:	AMBIT Microsystem Corp. [1468]
SDevice:	Device [0422]
Rev:	01

lspci -nnk (revision 01)

0c:00.0 Network controller [0280]: Broadcom Corporation BCM4311 802.11b/g WLAN [14e4:4311] (rev 01)
	Subsystem: Dell Wireless 1390 WLAN Mini-Card [1028:0007]
	Kernel driver in use: b43-pci-bridge
	Kernel modules: ssb

lspci -vmmnn (revision 02)

Slot:	01:00.0
Class:	Network controller [0280]
Vendor:	Broadcom Corporation [14e4]
Device:	BCM4311 802.11b/g WLAN [4311]
SVendor:	Hewlett-Packard Company [103c]
SDevice:	BCM4311 802.11b/g Wireless LAN Controller [1375]
Rev:	02

lspci -nnk (revision 02)

01:00.0 Network controller [0280]: Broadcom Corporation BCM4311 802.11b/g WLAN [14e4:4311] (rev 02)
	Subsystem: Hewlett-Packard Company BCM4311 802.11b/g Wireless LAN Controller [103c:1375]
	Kernel driver in use: b43-pci-bridge
	Kernel modules: ssb