SC4x0 Technical manual
Page 31 of 34
SeaCom
Rev
2.00
13.1.1 Power
Power supply voltage must be 18-32Vdc capable of delivering at least 1.5 A. It is internal fused by a
1.5A thermal fuse allowing peak current of more than 2A. Should be short circuit protected by a fuse
not larger than 2A.
Power input is protected against wrong polarization and over voltage. If connected wrong or voltage is
>33V, internal protection will short circuit to interrupt thermal fuse or disconnect external fuse.
Disconnect power to reset the internal fuse.
13.1.2 PE protective Earth
Should always be connected to earth / ships hull. The frame of the 410-type is connected to PE.
13.1.3 Line
Line tip & Line ring are the two wires of a standard 2 wire analogue telephone line. Idle voltage should
be approx 48V, Ringing voltage approx 90Vac RMS and busy line voltage approx 10Vdc.
13.1.4 Dimmer
Input for external common dimmer. Input is galvanic separated and span is 5 –28 volt. Input will source
approx 15 - 25mA from transmitter.
NOTE: Extern dimmer control is optionally.
13.1.5 Handset & cradle
Handset is connected using 4 wires or 6 wires. 2 wires for microphone, 2 wires for speaker and 2
wires for the hook switch. The cradle switch for hook signaling must be a potential free switch capable
of switching 30Vdc and must be in off state when handset is positioned in the cradle. Depending on
the type of hardware, switch may be located either in the handset or in the cradle.
The speaker output is short circuit protected by a 47ohm serial resistor. The max output current is
approx 20mA equivalent to 3mW in 8 ohm or 13mW in 32ohm.
NOTE: handset speaker should be 32 ohm or more & microphone must be condenser/electret type.
13.1.6 Relay output
This output is a potential free switch for remote indication of present ringing signal or for indication of
PA call e.i. it is used to signal a present call. Should be short circuit protected by a fuse not larger than
2A.
See technical specification for max. load of the relay switch.
If connected to an inductive DC load protection diodes should be connected as close to the load as
possible to protect other equipment from receiving high voltage transients.
If connected to an inductive AC load protection capacitor should be connected as close to the load as
possible to protect other equipment from receiving high voltage transients.
13.1.7 External speaker
This output is for connection of an external speaker or loudhailer. Output power is approx. 12watt.
Speaker must be 8 ohm or higher.
The power stage used, has thermal protection and will automatically shutdown if overloaded.
