HP Pavilion DV4000 Hardware And Software Manual page 123

Wireless (Select Models Only)
There are 3 popular implementations of WLAN adapters:
802.11b only
802.11b/g
802.11a/b/g
802.11b, the first popular WLAN standard, supports data rates of
up to 11 Mbps and operates at a frequency of 2.4 GHz. 802.11g,
which came later, also operates at 2.4 GHz but supports data rates
of up to 54 Mbps. An 802.11g WLAN device is backward
compatible with 802.11b devices, so they can operate on the same
network. 802.11a supports data rates of up to 54 Mbps but
operates at a frequency of 5 GHz. 802.11a is not compatible with
802.11b and 802.11g. For information on identifying the type of
device in your notebook, refer to
later in this chapter.
11–4
"Identifying a WLAN Device,"
Hardware and Software Guide