N2K0183 AP NETWORK
You can operate the N2K0183 multiplexer in two modes: AP or Client Station. In AP (Access Point) mode, N2K0183 creates a wifi network and smartphones, tablets or computers connect to this wifi network to receive/send data from/to N2K0183. In Client Station mode, N2K0183 joins an existing external wifi network and transmits/receives wifi data on that network. N2K0183 always creates its own AP network, even when you set N2K0183 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, N2K0183 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 192.168.5.2 ...). 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 N2K0183 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 N2K0183 to join that network as a Client Station, you should enter here the authentication parameters that N2K0183 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 be 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 succeds, the IP address will be shown in the header of this page just below the firmware version number.

SERIAL PORTS SETTINGS
The N2K0183 multiplexer has 2 input serial ports named as P1 and PX and one serial output port, named as P2. The serial input port PX is not directly accesible at the multiplexer screw connectors. In order to use PX you need to remove the lid of the case and identify the pads labelled as AX/BX from which you take wires externally. The baud rate of serial ports P1 and PX is adjustable between 4800, 9600, 19200 or 38400. The baud rate of port P2 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 if you route the serial inputs to the serial output. All data output by P2 is simultaneously output by the USB port of the multiplexer. Port P1 has a special mode of operation. If you set USB on the baud rate of port P1, data from that port is not input from the connectors A1/B1 but, instead, it is read from the USB port of the multiplexer. In that case data is read at the baud rate specified on P2. The wide text boxes for each serial port 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 P1 and PX can be transmitted to the output port P2 to wifi either using the UDP or the TCP ports or both and to an external (EXT) paired multiplexer It can also be converted to N2K messages and sent over the N2K bus.

N2K PORT SETTINGS
The N2K0183 multiplexer can receive and send N2K messages from and to the N2K bus. The received N2K messages from the N2K bus can be filtered and then converted to Nmea0183 sentences and routed to the serial port P2, to wifi (UDP or TCP) or to a paired multiplexer (EXT). On the other direction, Nmea0183 sentences from the serial input ports or from wifi can be filtered and then converted to N2K messages to be transmitted over the N2K bus. In order to set a filter for the incoming N2K messages see the the note 'N2K message filtering' below. In the case of the outgoing Nmea0183 sentences see the note 'Nmea0183 sentence filtering' below. If you do not want filtering, just enter 0 (zero) in the filtering wide text boxes. Only a small set of Nmea0183 sentences is capable of being translated to N2K messages and vice versa. You can also select advanced settings for the operation of multiplexer by pressing the shown button.

WIFI PORTS SETTINGS
The N2K0183 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 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, N2K0183 transmits using 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 sent by the multiplexer. You should also set the same protocol (UDP or TCP) and the corresponding port numbers on the connection devices that receive/send data from/to the N2K0183 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 Nmea0183 sentence filtering. Finally you can set what to do with the received wifi data. It can be be transmitted to the serial output port P2, to the N2K bus, to the EXT output for a paired multiplexer or to the other internet port.

NMEA0183 SENTENCE FILTERING
The N2K0183 multiplexer is capable of filtering Nmea0183 sentences arriving at the 2 input serial ports and at the UDP and TCP input ports. It can also filter Nmea0183 sentences before transmission on the output serial port or before being converted and transmitted on the N2K bus. Filtering is a process that we can use to pass or to block specified Nmea0183 sentences. The filtering is governed by a 'filtering string' of up to 40 characters that you can enter in the wide text boxes for each of the ports referred to above. There are some differences to previous multiplexers on how you construct the filtering strings and on how they operate. The first character is a number, between 0 and 9. When this number is 0 and nothing follows, no filtering takes place. When this number is 9, the port is ignored (neither read nor written by the multiplexer). When this number is between 1 and 8, a sequence of successive sentences is periodically dropped independently of the rest of the filtering string. For example, if that number is 4, it means that 4 successive sequences are dropped and only the following one is taken for filtering analysis. The second character can only be 'Y' or 'N' and refers to the checksum of the Nmea0183 sentence. If the character is 'Y', the checksum of the sentence is verified and the sentence is ignored if the checksum is not correct. If the character is 'N', no checksum verification is performed. The filtering strings '0' and '0N' are equivalent 'all-pass' filters, and '0Y' blocks sentences with a wrong checksum. 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 (pass through) by 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. The fourth character is a separator. We will use '-' as a separator but characters such as '+', '.', '~' and others can also be used. Nmea0183 sentences are specified by 5 characters. The starting 2 characters refer to the talker ID and the following 3 characters characterize the TYPE of sentence. You can specify up to 6 sentences to be accepted or to be rejected using the maximum length 40 of the filtering string. Following are some examples of filtering strings. If you want a port to pass only the sentence DBT (Depth Below Transducer) generated by a source with ID SD (Sounder, Depth) you can use the string '0YA-SDDBT'. If the filter is to pass only DBT sentences independently of the talker ID, you use '0YA-0DDBT' as a talker ID starting with 0 is ignored. In the same way a TYPE starting with 0 is ignored. For example, the filtering string '0YR-SD0BT' rejects any TYPE of sentence generated by a talker with ID equal to SD. An example of a string that specifies 2 sentences is '0NA-IIDBT-0XRMC'. It means that the filter only passes DBT sentences generated by a talker ID of II and RMC sentences whatever is the talker ID. 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.

N2K MESSAGE FILTERING
N2K message filtering refers to the filtering of the messages read from the N2K bus before they are converted to Nmea0183 sentences. We suggest that you read first the topic about Nmea0183 sentence filtering as there are similarities (and differences). In both cases you need to enter a text string of characters that define the (only) messages that you want to accept or to reject. In this case, the starting character can only take 3 values: '0' (no filtering) 'A' (accept only) or 'R' (Reject only). If this character is '0' nothing should follow. On the contrary, if the starting character is 'A' or 'R', at least one N2K message should follow. The starting character and the N2K messages must be spaced by a separator character as in the Nmea0183 filtering case. All N2K messages have a header that, among other things, defines its type or PGN (Parameter Group Number) and its SRC (Source Address). We specify a N2K message in a filtering string by a sequence of 7 hexadecimal characters. These characters are the decimal digits 0 to 9 and the capital letters A to F. The first 2 characters refer to the SRC and the remaining 5 characters refer to the PGN. If you use Debug Mode you can see all the messages that travel on the N2K bus and its equivalent hexadecimal string inside square brackets. The filtering string A-211F50B, for example, means that only PGN 1F50B (or 128267 in decimal) originated by SRC 21 (or 33 in decimal) passes the filter. If we wanted the referred to PGN to pass the filter independently of the SRC, we would use A-X11F50B as the character X at the start of the SRC definition means that the SRC should be ignored. In the same way, the character X at the start of the PGN definition (3rd position) means that the PGN should be ignored. Therefore the string A-21XF50B means that only N2K messages generated by source 21 (or 33 in decimal) are accepted.

SETTING OPERATING MODES
In addition to the above parameters, you have 4 radio buttons to choose between: (i) working in AP mode only (ii) also connect as a Client Station (iii) Simulation Mode (iv) Debug Mode. You press the SET button for N2K0183 to accept the parameters in this page. If there are no errors in the parameters, N2K0183 changes its operation to the mode and settings selected. You can use a Windows tool called 'Nmea0183Tester.exe' for advanced testing of the multiplexer. The tool can transmit or record NMEA 0183 data using WiFi or serial communication. Please check www.vela-navega.com/forum to obtain support for the multiplexer.

HARD RESET AND UPDATE
When you press the HARD RESET button the multiplexer loads its factory settings. When you press the UPDATE button you can check and load the latest available software for the multiplexer. The factory setting uses the following parameters: Mode: Access Point; Ssid: N2K0183; Password: 12345678; IP Address: 192.168.4.1; Wifi Protocol: UDP; UDP Port Number: 2000; Serial Port P1 Baud Rate: 4800; Serial Ports PX and P2 Baud Rates: 38400; Serial Output P2: none; UDP Output: P1.