Connector panel of the BDU
98-175666-A
Chapter 3: Interfaces
3-3
NMEA 0183
The NMEA 0183 connection supports IEC 61162-1 and IEC 61162-2.
• IEC 61162-1, baud rate 4800, format 8N1.
• IEC 61162-2, baud rate 38400, format 8N1.
The baud rate is auto detected by the BDU, the user cannot configure this interface.
Supported NMEA strings in order of priority:
1. HEHDT (North seeking Gyro compass)
2. GPHDT (GPS compass)
3. HNHDT (Non-North seeking gyro compass)
4. IIHDT (Integrated Instrument)
5. HCHDT (Magnetic compass)
Recommended NMEA 0183 cable:
Ethernet Cat. 5 or better.
3.1.5 GPIO RJ-45 connector
The Tx mute function can be controlled with a simple switch connected between pin 1 (Tx
mute) and pin 2 (12 VDC). The Rx lock function is high and becomes low when the modem
is not in Rx lock.
Note
Any HDT sentence is supported as long as it complies with the following header
format: "$xxHDT" where xx can be two characters e.g. IN for $INHDT.
Outline on BDU Pin
I/O Signal
Pin function
1
I
GPIO1
Tx mute (active high)
2
O
12 VDC / 500 mA Power output
3
O
GPIO2
Rx lock (open drain)
4
N/A GPIO3
Future use
5
GND
Ground
6
O
12 VDC / 500 mA Power output
7
N/A GPIO4
Future use
8
GND
Ground
Shield
PCB ground
PCB ground
Table 3-5: RJ-45 GPIO connector, outline and pin assignment
