Manual - yappelectronics.co.uk

YAPP NMEA-0183 Multiplexer and Rate Changer
Overview
This device has 2 purposes:
1) It can multiplex 3 NMEA-0183 data stream into 1.
2) It can change the rate of one of the NMEA-0183 input stream from 4.8 kbaud
to 38.4 kbaud.
3) Or do both of those at the same time.
The device has 3 inputs and 2 outputs. The 2 outputs transmit the same data but at
different voltage levels : RS-232 levels and RS-422 levels. The reason for these 2
output types is that the NMEA-0183 standard changed from the former to the latter
during its life.
NMEA-0183 runs at one of two rates – 4.8 kbaud and 38.4 kbaud. The higher rate is
usually used for AIS data streams only. All others are normally at 4.8 kbaud.
Configuration
Only input 1 of the 3 inputs can accept data at 38.4 kbaud. Inputs 2 and 3 always
require data at 4.8 kbaud. Input 1 and the output run at the same rate. It is not possible
to have 3 inputs at the low speed and the output at the high speed.
The rate of input 1 and the output is controlled by a shorting link on the board. When
the shorting link is in place across the pins the following configuration is used:
Input 1:
Input 2:
Input 3:
Output:
4.8 kbaud
4.8 kbaud
4.8 kbaud
4.8 kbaud
When the shorting link is removed from the pins the following configuration is used:
Input 1:
Input 2:
Input 3:
Output:
38.4 kbaud
4.8 kbaud
4.8 kbaud
38.4 kbaud
This shorting link is shown in the red circle and is labelled BAUD on the board:
Connections
The device requires a 12 Volt supply connected to the connector labelled POWER:
The 3 inputs are labelled NMEA1, NMEA2 and NMEA3. Only NMEA1 input can
have the rate it accepts data changed:
The RS-232 level output is labelled RS232OUT:
The RS-422 level output is labelled NMEA OUT:
The device you are connecting to the inputs will call their connections a variety of
terms. The list below shows what you should connect to what…
Remote device connection name to connect to this device’s RxD/A
NMEA+
A
Data
TxD
Remote device connection name to connect to this device’s GND/B
NMEAB
GND or GROUND
0V
The device you are connecting the output to will call their connections a variety of
terms. This is what you should connect to what…
Remote device connection name to connect this device’s NMEA+ or DATA to
NMEA+
Data
A
RxD
Remote device connection name to connect this device’s NMEA- or GND to
NMEAGND or GROUND
B
0V
Which Output to Use?
NMEA-0183 devices use either RS-232 voltage levels or RS-422 voltage levels –
there is no consistency. However, it is a requirement for all NMEA-0183 listeners to
be able to accept RS-232 voltage levels. Therefore try the RS-232 output first
(labelled RS232 OUT). If this does not work, try the RS-422 output (labelled NMEA
OUT). Only one of the 2 outputs should be used at a time.

Download Report