Draytek 5500 Series manual Channel, Hide Ssid, Long Preamble

11b only - The radio only supports IEEE802.11b.

Index (1-15)	Set the wireless LAN to work at certain time interval
	only. You may choose up to 4 schedules out of the 15
	schedules pre-defined in Applications >> Schedule
	setup. The default setting of this filed is blank and the
	function will always work.
SSID	The default SSID is "default". We suggest you change it
	to a particular name. It is the identification of the wireless
	LAN. SSID can be any text numbers or various special
	characters.
Channel	The channel of frequency of the wireless LAN. The
	default channel is 6. You may switch channel if the
	selected channel is under serious interference.

Hide SSID	Check it to prevent from wireless sniffing and make it
	harder for unauthorized clients or STAs to join your
	wireless LAN. Depending on the wireless utility, the user
	may only see the information except SSID or just cannot
	see any thing about Vigor wireless router while site
	surveying.
Long Preamble	This option is to define the length of the sync field in an
	802.11 packet. Most modern wireless network uses short
	preamble with 56 bit sync filed instead of long preamble
	with 128 bit sync field. However, some original 11b
	wireless network devices only support long preamble.
	Check it to use Long Preamble if needed to
	communicate with this kind of devices.

136 VigorPro5500 Series User’s Guide