6.0 SSID, Channel, Encryption and Authentication
WSN802G modules support SSID, channel, encryption and authentication mode options for three access
point connections plus an Ad Hoc connection. The SSID, channel, encryption and authentication mode
options are summarized in Tables 4.14.1 and 4.14.6 in Section 14 above.
6.1 Connection Scanning
To establish an 802.11b/g/n connection, WSN802G modules will scan for Access Point 1, then 2, then 3
and then switch to Ad Hoc server mode and broadcast for a connection. This sequence repeats until a
connection is established. This scanning sequence is automatic. Note that failure to make a quick con-
nection will adversely affect battery operating life.
6.2 Ad Hoc Mode
WSN802G modules support Ad Hoc operation. Ad Hoc operation is an 802.11 mode where two non-
access point devices (sometimes called non-infrastructure devices) communicate directly with each other
in a point-to-point network. Ad Hoc mode can be used to configure a WSN802G device over a wireless
link without needing an access point.
In an Ad Hoc network, there are server nodes and client nodes. Server nodes broadcast their presence
and client nodes, once they have heard a server node, will request to join. Some devices, such as PCs,
can operate as both a client and a server, where they broadcast their presence but also listen for other
devices that are advertising their presence. The WSN802G module acts only as a server. That is, it ad-
vertises its presence and waits for requests from client devices to join.
The WSN802G module will automatically enter Ad Hoc mode if it is unable to join any of the three net-
works specified in the preferred SSID parameters. To operate in Ad Hoc mode, the WSN802G module
must have DHCP disabled, have an IP address statically assigned as well as a subnet mask and a gate-
way IP address. These values can be set through the serial port in Bank 7, or through SNMP commands.
Refer to Sections 4 and 7 in this manual for details. Since an Ad Hoc session will terminate if a WSN-
802G module enters sleep mode, the module should be kept awake by asserting the WAKE_IN signal.
When the WSN802G module is in Ad Hoc mode it will advertise itself using the SSID “RFM-
macaddress
”
where
macaddress
is an ASCII string of the module’s MAC address with the colons between values re-
moved. A device wishing to join the WSN802G Ad Hoc network must have a statically set IP address that
is on the same subnet as the WSN802G IP address. The WSN802G module Ad Hoc mode also allows
the choice of an RF channel and encryption mode. A device wanting to join the WSN802G Ad Hoc net-
work must have these parameters agree with the values set in the WSN802G module.
When operating in Ad Hoc mode, the WSN802G module will operate in the same way as when it is con-
nected to an access point. This means the module will send Linkup and Config Traps as when in normal
access point operation. A device connected to the WSN802G module can simply ignore these transmis-
sions.
©2009-2015 by Murata Electronics N.A., Inc.
HN-210D/X, HN-214 D/X Rev. 2.0 01-16-15
Page 40 of 101
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