Furuno CI-88 Installation Manual page 47

4.3.2 Suppressing interference
Input
Up to two interfering equipment can be connected to the interference rejection circuit in the
transceiver unit via EX KP IN 1 or EX KP IN 2 port. This circuit receives the keying pulse
(KP) from the interfering equipment to reject interference.
PCN (66P3924)
TB-4
H
9
EKP1
C
16
H
11
EKP2
C
12
Check of keying pulse
The following keying pulse is required from the interfering equipment.
0 V
If the level is out of the ratings or KP output circuit is not provided, take the measures
shown on the next two pages to prevent equipment malfunction.
Buffer circuit for positive-going KP
Interfering
Equipment
TP2
TP4
Interference rejection circuit
5 to 15V
Keying pulse needed
KP out
2K
Approx.
300
Additional Circuit
CR14
[EKP1]
Photo
Coupler
CR15
[EKP2]
Photo
Coupler
less than 1 V
CI-8810
5 to 15V
Approx.
300
Interference
Rejector
4. ADJUSTMENT
Flip
Flop
Circuit
S1
TB4
H
C
4-13