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© 2015 Active Research Limited
OPTO Inputs
The differential opto-isolated inputs are designed to handle
a variety of NMEA 0183 device output specifications.
Please determine (from device manufacturer’s information)
if the device(s) required to be connected to the NDC-4
conforms in full to the NMEA 0183 network communication
standard. If it does not, the flexible NDC-4 inputs should
still be capable of interfacing with the device, though this is
not guaranteed.
The diagram above shows a typical installation with both
fully compliant NMEA devices with differential inputs/
outputs, and non-differential output devices.
Note:
All NDC-4 inputs are identical and the connections
shown are examples that can be used on every input port.
NMEA Talker Devices 1 and 2:
These devices conform in
full to the NMEA 0183 standard. Talker 1 shares the same
connection ID’s as the NDC-4, so connection is a simple
matter of matching the ID’s. Connect
‘+’
to
‘+/A’
and
‘-’
to
‘-/B’
or
‘A‘
to
‘+/A‘
and
‘B’
to
‘-/B’
(
refer to figure 2
).
NMEA Talker Devices 3 and 4:
These devices do not
conform completely to the NMEA 0183 standard. However,
by connecting
‘+‘
to
‘+/A‘
or
‘Data/Signal’
to
‘+/A‘
and
‘G/
Ground’
to
‘-/B’
the NDC-4 should receive the NMEA data
correctly.
ISO-Drive Outputs
The ISO-Drive outputs are capable of driving up to 10
NMEA 0183 fully compliant listening devices, or a mixture
of NMEA 0183 devices and a Personal Computer (PC)
communication port. However, if you wish to maintain
isolation between all devices, then only
one
listening
device should be connected to an ISO-Drive output.
NMEA Listener Device’s B and C:
These devices
conform in full to the NMEA 0183 standard and their
connection ID’s match that of the NDC-4.
Personal Computer:
Whilst the OPTO IN 0 and ISO-
Drive 0 provide a bidirectional RS232 compatible port for
connection to a PC, the ISO-Drive 1 output is also capable
of being read by a PC’s RS232 port. Simply connect
‘+/A’
to
‘Rx’
and
’-/B’
to
‘G/Ground’
on a standard D-type
connector. See “Figure 26 - DB9 Connection” on page 8
of the “Full user manual” available on the CD and from
for a diagram of this wiring
connection.
NMEA Listener Device A:
This device does not conform
in full to the NMEA 0183 standard. However, by connecting
‘+/A‘
to
‘+‘
or
‘Data/Signal’
and
‘-/B’
to
‘G/Ground’
the
device should be able to receive the NMEA data correctly,
though this is not guaranteed.
Note:
Wire colours are for guidance only.
Connecting to NMEA Devices
Figure 2 – NMEA 0183 connections
NMEA DA
TA COMBINER
99999
NDC
-4-A-USB
NMEA
Talker 3
+
G
NMEA
Talker 1
+
-
NMEA
Talker 2
A
B
NMEA
Talker 4
D
Personal
Computer
Rx
G
NMEA
Listener A
+
G
NMEA
Listener B
+
-
NMEA
Listener C
A
B
G
Summary of Contents for NDC-4
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