Computers with wireless network cards send requests to see whether there are wireless access points to which they can connect.
To configure an XTM device wireless interface to send and answer these requests, select the Broadcast SSID and respond to SSID queries check box. For security, enable this option only while you configure computers on your network to connect to the XTM wireless device. Disable this option after all your clients are configured. If you use the wireless guest services feature, it can be necessary to allow SSID broadcasts in standard operation.
Change the SSID
About Wireless Configuration Settings