INSTALLATION
In order to install the
multiplexer you need to remove the cover of the plastic box to get
access to the Printed Circuit Board (PCB) where you find Screw
Terminal Connectors. The power supply connector has 2 pins
labelled 12V (positive) and GND (negative). The 4 serial input
ports have labels A1 and B1, A2 and B2, A3 and B3 and A4 and B4.
The output serial port has labels A5, B5 and GND. The PCB has a
recess to facilitate the entry of the cables.
The way you connect external devices to the multiplexer depends on
their type. Output devices can be of 2 types: Single Ended Output
devices and Differential Output devices. All the 4 inputs (P1, P2,
P3 and P4) of the Nmea4Wifi multiplexer use opto-couplers which
facilitates the connections and offers extended noise
immunity. Input devices to which we connect the P5
multiplexer output can also exist in 2 types: Single Ended Input
devices and Differential Input devices. We now discuss all the
possible cases.
The connections of output devices (also referred to as Nmea 0183
talkers) to the multiplexer are shown in the next picture. If your
Nmea data is available though a Differential Output device, the
preferred way is to connect its A (or Nmea+) terminal to the
multiplexer A and its B (or Nmea-) terminal to the multiplexer B.
You could also connect GND to B. If your Nmea data is available
through a Single Ended Output device (such as RS-232) you connect
its Output terminal to the multiplexer A and its Ground (or
common) terminal to the multiplexer B.
We now consider the connection of the output serial port P5 which
uses a 3-way screw connector with labels A5 B5 and GND. If the
receiving device has an opto-isolated port, you connect A5 to the
A (or Nmea+) terminal of the receiving device and B5 to the B (or
Nmea-) terminal of the receiving device. You could also connect
GND to B (or Nmea-). If the input port of the receiving device is
not opto-isolated you should take special attention to the
connections. You should connect A5 to the input terminal of the
receiving device and not use B5. In addition, both GNDs
(multiplexer and receiving device) should be connected together.
