Specifications

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N: Set the network parameters of the WiFi connection:
$PSMDWI,N,ip,mask,gw[*hh]<CR><LF>
ip: IP address, 0 for automatic assignment by a DHCP server
mask: network mask
gw: optional gateway address
$PSMDWI,N,0 sets the multiplexer to DCHP in order to obtain all settings automatically.
The gateway address is only needed to obtain firmware updates of the WiFi module. When
the ip field contains a ‘0’, the IP settings will be obtained from a DHCP server and all other
fields will be ignored. Fields may be omitted for parameters that need no change. For
instance: $PSMDWI,N,,,192.168.1.1 only sets the gateway address.
T: Set the multiplexer to Terminal Mode. This opens a direct communication channel from the
wired host interface to the wireless module. A terminal program can then be used to
communicate directly with the wireless module. The multiplexer can be set to normal (NMEA)
mode by a power cycle or by typing a ctrl-q character. See section Terminal Mode for more
details
In Terminal Mode, the multiplexer does not respond to any proprietary NMEA commands, nor
will it operate as a multiplexer.
U: Update the firmware in the WiFi module. Before using this command, the multiplexer must
be configured to connect to an existing access point with a connection to the Internet. This
can be accomplished with the W and the N sub-commands.
V: Return the version number of the WiFi firmware. A $PSMDWI,x.xx sentence is returned.
W: Set the WLAN parameters of the WiFi connection:
$PSMDWI,W,mode,ssid,[phrase][*hh]<CR><LF>
mode: A = Access Point, I = Infrastructure
ssid: SSID of the WiFi connection
phrase: Optional pass phrase (only for Infrastructure mode)
When Access Point mode is set, the radio channel is set to 1 and the IP address/netmask are
set to 10.0.0.1/255.255.255.0. They may be changed with the ‘N’ sub-command.
When Infrastructure mode is set, the radio channel is selected automatically and DHCP is
enabled. The previously stored IP address/netmask are retained in case the multiplexer does
not receive these from a DHCP server or access point.
Z: Configure the WiFi module for production testing
If any of the above commands fails, the wireless module may still be in Command Mode, indicated
by a $PSMDWC response instead of $PSMDWI. To switch the multiplexer back to normal, a
$PSMDWI sentence must be issued without any parameters.
Command Mode
The sub commands listed above are used to change the most common settings of the wireless
module by means of an NMEA sentence. The PSMDWI,A sentence for instance, sets over 25
parameters in the WiFi module automatically. In some cases, it is necessary to fine tune individual
settings of the wireless module. Command Mode allows sending special commands to the module
using an NMEA sentence. For instance, if you would need to change the MTU value of the WiFi
connection, you can use the following sentences to do this:
$PSMDWI,C (enter command mode)
$PSMDWI,set ip mtu 600 (set the MTU value to 600)
$PSMDWI (exit command mode)
The second sentence sends the command ‘set ip mtu 600’ to the WiFi module.
The general format of a direct command sentence is:
$PSMDWI,command,[response],[time out][*hh]<CR><LF
command: command to be sent to the wireless module.
[response]: optional expected response.
[time out]: optional time out value of 1..9 seconds. Standard time out is 1 second.
If an optional expected response is specified, the multiplexer returns either of two sentences:
$PSMDWC,OK (the module returned the expected response)
$PSMDWC,No Response (the expected response was not received)