NMEA4WIFI AP NETWORK
You can operate the NMEA4WIFI multiplexer in two modes: AP or
Client Station. In AP (Access Point) mode, NMEA4WIFI creates a
wifi network and smartphones, tablets or computers connect to
this wifi network to receive/send data from/to NMEA4WIFI. In
Client Station mode, NMEA4WIFI joins an existing external wifi
network and transmits/receives wifi data on that network.
NMEA4WIFI always creates its own AP network, even when you set
NMEA4WIFI to join an existing network. In this panel, you
specify the name and the password of the wifi network that
smartphones, tablets and computers should use to join this
network. When working as an Access Point, NMEA4WIFI uses IP
address 192.168.4.1 and supports DHCP. A maximum of 5 clients
can join the network and are assigned consecutive IP addresses
(eg 192.168.4.2 ...). Security is WPA2-PSK. Ssid and Password
can have a maximum of 15 characters and a minimum of 4 and 8
characters, respectively. When you need to change any setting of
NMEA4WIFI you should connect to this network and then write
192.168.4.1 in the navigation bar of a browser to get the page
that you are reading now.
EXTERNAL NETWORK
If you have already a working wifi network and want NMEA4WIFI to
join that network as a Client Station, you should enter here the
authentication parameters that NEMA2WIFI should use to join this
existing network. Ssid and Password can have a maximum and a
minimum size of characters as before. The IP address of the
multiplexer on this external network can assigned by DHCP or it
can be a static one. In order for the multiplexer to obtain an
automatic IP from the network/router you enter 0 in the IP
Address text box (this is the default). In order to force a
static IP you need to specify it, exactly, on the IP Address
text box. Make sure that you enter an unused IP belonging to the
DHCP pool of the existing network or router. When the connection
to an existing network succeeds, the IP address will be shown
here: (X.X.X.X).
SERIAL PORTS SETTINGS
NMEA4WIFI has four input serial ports named as P#1, P#2, P#3 and
P#4 and one serial output port, named as P#5. The baud rate of
serial ports P#1 and P#2 is adjustable between 4800, 9600, 19200
or 38400. The baud rate of P#3 and P#4 can be 4800 or 9600 baud.
The baud rate of port P#5 can be 4800, 9600, 19200, 38400, 57600
or 115200. It is important to note that if the baud rate of the
output port is inferior to those of the input ports, data may be
lost. Also, all data output by P#5 is also output by the USB
port of the processor module of the multiplexer. Ports P#1 and
P#4 have special modes of operation. If you set USB on the baud
rate of port P#1, data from that port is not input from the PCB
connector but, instead, it is read from the USB port of the
processor module. In that case data is read at the baud rate
specified on P#5. The special mode of P#4 is called SeaTalk. If
you choose that mode data is assumed to be in the SeaTalk format
and it is immediately translated to the Nmea 0183 format. The
wide text boxes for each serial ports refer to NMEA0183 sentence
filtering. If you do not need sentence filtering, you enter 0
(zero) in these boxes. See below for an explanation about
sentence filtering. Data received on the input ports P#1, P#2,
P#3 and P#4 can be transmitted by output port P#5 or by wifi
either using the UDP port, the TCP port or both.
WIFI SETTINGS
The NMEA4WIFI multiplexer can send and receive wifi data in a
"client/server configuration" where the multiplexer is the
server and the connecting devices are the clients. You can can
use either the UDP, the TCP or both internet protocols to send
and receive wifi data. You turn one protocol inactive by setting
its port number equal to zero. Non zero port numbers, either UDP
or TCP, should be in range from 1024 up to 65535. By default,
NMEA4WIFI uses UDP broadcasting on port number 2000 (compatible
with Navionics Sonar Chart Live). UDP broadcasting assures that
all the clients connected to the wifi network listening to the
specified UDP port number will receive the packets by the
multiplexer. You should also set the same protocol (UDP or TCP)
and the corresponding port numbers on the connection device(s)
that receive/send data from/to the NMEA4WIFI multiplexer. When
you use the TPC protocol, you need to specify the IP address of
the multiplexer. This address, in the case of AP ONLY mode, is
192.168.4.1. If the multiplexer is connected to an external
network you specify the IP address that is assigned by the
external network. It is important to note that only one
connection with the multiplexer can be active through the TCP
protocol but, at the same time, you can have multiple UDP
connections. The wide text boxes for each wifi ports refer to
NMEA0183 sentence filtering. If you do not need sentence
filtering, you enter 0 (zero) in these boxes. See below for an
explanation about sentence filtering. Finally you can set what
to do with the received wifi data. It can be be transmitted
through the serial output port P#5 or through the other internet
port.
NMEA0183 SENTENCE FILTERING
The 4 input serial ports, the serial output port and the 2 input
wifi ports can be set to pass or to block certain NMEA0183
sentences. This is governed by a filtering string of up to 43
characters that you can enter in the wide text boxes for each of
the referred to ports. The first character is a number, between
0 and 9. When this number is 0 no filtering takes place. When
the number is 9 the input is completed ignored (not even read by
the multiplexer). When the number is between 1 and 8, it
specifies the number of sequences that are periodically dropped
independently of the rest of the filtering string. For example,
if that number is 3, it means that on 4 sucessive sequences, one
is taken and three are dropped. The second character should be a
separator. The characters "-", ".", "~" and others could be used
as separators but we will use "-". The third character can only
be "A" or "R". "A" means that only the sentences that are
referred to in the rest of the filtering string are ACCEPTED by
(pass through) the ports. "R" means that only the sentences that
are referred to in the rest of the filtering string are REJECTED
(blocked) by the ports. Each NMEA0183 sequence is specified by 3
characters inserted between separators. For example, the string
"2-A-RMC-GGA-GLL-GRS-GSA" means that only 1 in 3 successive
sentences is considered and the considered sequence only passes
if it is 1 of the 5 that are specified. It is interesting to
note that the shown sequence has a length of 23 characters and
specifies 5 sentences. For each additional sentence you need 4
more characters (the separator and the 3 characters). Therefore,
in order to specify 10 sentences we need 43 characters which is
maximum length of the filtering string. An important note is to
understand that the filtering strings for the UDP and TCP ports
refer to data input. No filtering takes place when data is
transmitted by UDP or TCP.
SETTING OPERATING MODES
In addition to the above parameters, you have 2 radio buttons to
choose between: (i) working in AP mode only or (ii) also connect
as a Client Station. You press the SET button for NMEA4WIFI to
accept the parameters in this page. If there are no errors in
the parameters, NMEA4WIFI changes its operation to the mode and
settings selected. IMPORTANT NOTE: you can use a Windows
Programme (or tool) to configure the multiplexer as described in
this page. The tool is also very useful to set NMEA 0183
sentence filtering, to update new firmware if available, to test
the multiplexer or to record received NMEA 0183 data. Please
check www.vela-navega.com/forum to get this programme or to
obtain support for the multiplexer.
FACTORY SETTINGS
Pressing the Set Factory Defaults button is the same as an
hardware reset of the system. The factory setting uses the
following parameters: Mode: Access Point; Ssid: NMEA4WIFI;
Password: 12345678; IP Address: 192.168.4.1; Wifi Protocol: UDP;
UDP Port Number: 2000; Serial Port P#1, P#3 and P#4 Baud Rates:
4800; Serial Ports P#2 and P#5 Baud Rates: 38400; Serial Output
on P#5: none; UDP Output: P#1 and P#2.