Furuno Doppler Speedlog DS-50 Installation Manual page 37

2. NMEA I/O circuit
5V
470Ω
The maximum allowable current in the NMEA output line is 25 mA and recommended
current is 10 mA. When terminating the line by a photo coupler for current loop
configuration, take suitable means at the signal receive side to limit the current. If, for
example, forward voltage drop in the coupler is 2.2 V;
[4.8 – 2.2 (V)] / [10 (mA)] – 227 ( ) = 33 ( )
therefore, insert a 33 ohm resistor in series in the line.
CIF: ON
5V
NMEA: OFF
J2/J3
SRCN2A16/10S SRCN6A16/10P
180Ω 47Ω
22Ω
47Ω
47Ω
22Ω
NC
NC
Figure 5-10 NMEA I/O circuit
5.3 Remarks on Connection of Other Equipment
1
TXD-H
TXD-C
2
RXD-H
3
4
RXD-C
5
9
10
CO-0, 2x5P
MAX 25mA
30