NMEA Data Multiplexer - NDC-4
Page 9
© 2015 Active Research Limited
Other Connections
Figure 3 – RS232, USB and Battery connections
Battery /
Power Supply
+
-
PC or
Laptop
USB
PC or
Laptop
Rx
Tx
G
Connecting to the Battery Supply
The NDC-4 can be powered either by the USB connection
or through an external power source. If both power sources
are available, the precautions in the USB warning section
above must be adhered to.
If the NDC-4 is powered from an external power source,
like a battery, it should be wired to the vessel’s battery
supply in the most direct manner possible, to minimize
interference from other electronic devices. The cable used
should be of sufficient gauge to handle the power
requirements of the NDC-4 (refer to
USB Warning!
USB power and battery power are NOT
isolated from each other. Consult a qualified installer to
ensure there is no ground loop hazard when connecting
both. Disconnecting a single battery lead or turning off
the supply does NOT prevent this ground loop hazard.
Ground loop damage is NOT covered by the guarantee.
For installs where the NDC-4 must still operate when
the PC is switched off, full PC isolation can be
maintained by using Port 0 (‘OPTO IN 0’ and ‘ISO OUT
0’) as the PC connection.
Only when using a laptop running on its internal battery
(with NO charging supply), can the NDC-4 USB cable
be used at the same time as powering the NDC-4 from
the ships battery on the “BATT” terminals.
!
Connecting to a Personal Computer
The USB port can be used to connect a PC to the NMEA
0183 system. A USB cable is available in the form of an
upgrade kit for variants that do not come with a cable. The
part number will include “USB” if a cable is provided with
that variant (e.g. NDC-4-USB).
Alternatively, Port 0 (OPTO IN 0 and ISO OUT 0) can be
used to connect a PC into the NMEA 0183 system by
using a serial port cable conforming to the following
specification:
1.
A D-type female (socket) connector for the PC end of
the cable.
2.
A minimum of 3 cores are required in a shielded cable.
Higher quality cable will yield higher performance (SNR).
Most typical cables have two twisted pairs inside. In this
case, use one pair for the
TX
line and one for the
RX
line.
Use the spare wire in each pair as ground, and connect
the cable shield to ground only at the computer end.
3.
The
TX
of the NDC-4 should be connected to the
RX
of
the computer (standard D-type,
pin 2
) and the NDC-4
RX
should be connected to the
TX
of the computer (
pin 3
).
The
GND
of both IN 0 and OUT 0 on the NDC-4 should be
connected to the PC’s serial port ground (
pin 5
). See
“Figure 26 - DB9 Connection” on page 9
of the “Full user
manual” available on the CD and from
for a diagram of this wiring connection.
Note:
Wire colours are for guidance only.
Summary of Contents for NDC-4
Page 2: ......
