Linksys WRT54GL Instruction Manual page 7

Sherpa 7
Image Source : Linksys, Cisco Systems
9. You can type in any name for your wireless network in the box next to Wireless
Network Name(SSID). You can also choose to either Enable or Disable Wireless
SSID Broadcast. If it is disabled, your wireless network cannot be seen/discovered
publicly by other electronic devices that are cable of connecting to wireless
networks. By default, it is enabled.
10. Now click on the Wireless Security sub-tab under Wireless. You should be able
to see the following options.