in the era of 802.11b and 802.11g being the hottest and greatest thing for wireless clients, there were very few desktop PCs equipped with interface cards for it.

generally it was built into laptops for 95% of the clients... Your typical Dell business laptop from the year 2000 came with a minipci slot and a 2.4 GHz antenna cable, populating the slot with an 802.11b card was an option.

or something like the original apple airport wireless AP and the wifi 802.11b built into macbooks from the era.

or in an even earlier era you would find like PCMCIA/PC Card type 2 or type 3 interfaces with an 802.11b radio and antenna in them to stick out the side of your laptop.