The SSID on wireless clients can be set either manually, by entering the SSID into the client network settings, or automatically, by leaving the SSID unspecified or blank. A network administrator often uses a public SSID, that is set on the access point and broadcast to all wireless devices in range. Some newer wireless access points disable the automatic SSID broadcast feature in an attempt to improve network security.
SSIDs are case sensitive text strings. The SSID is a sequence of alphanumeric characters (letters or numbers). SSIDs have a maximum length of 32 characters.See also - What is a Network Name?