SC4x0 Technical manual
Page 20 of 34
SeaCom
Rev
2.00
9. Mounting & programming
When setting up this unit, first disassemble the box if it is a 420 type.
Detach the terminals J4 & J6 by pulling them off. Connect all wires to the terminals and check power
and relay connections before attaching the terminals to the unit. Be careful not to relocate J4 at J6.
9.1 Power supply & grounding considerations
If powered from the exchange, make sure a fuse protects the unit and power supply is strong enough
to blow the fuse without shutting down the exchange. If more units are connected, make sure the
power supply has enough dynamic power to handle peak currents if external speakers are connected.
The telephone will consume approx 250mA max if no external speaker is connected. An 8ohm
speaker will take additional peak currents up to at least 1.8 amp.
Both the 410 & the 420 must have connected PE via a separate wire to a central earth/grounding
point.
9.2 Programming the type of headset & VOX
When using headset, always check the type of microphone. If it comes with an eletrect (condenser)
type, changes needed to be made to factory settings. Enter the menu system to select matching type.
Always make gain adjustments AFTER selecting type of microphone.
The headset can be used with full duplex or in PTT mode. However, in full duplex mode when
connected to another phone using hands free, some voice control may be needed to maintain control
of speech direction.
VOX will raise or lower gain towards the line for better speech detection at the hands free end. This
will enhance the speech quality by raising the gain when speaking into the headset microphone and
lower it when not. If voice switching is used at the hands free end, it will ease the detection of speech.
However, if speaking at the same time, it may difficult to hear what is said at both ends, so it requires a
little practice to learn to speak in shift for perfect connection.
9.3 Adjusting microphone gain
A key issue for best performance is correct adjusted microphone gain. This phone is designed for use
in very noisy areas but may just as well be used In quiet areas. However, this dynamic span can only
be achieved by adapting the microphone gain to the actual installation.
In most cases factory settings will work just fine. However, if used in noisy areas, gain must be
lowered to avoid distortion and signal saturation. A high level of background noise requires the user to
speak very loud.
When speaking very loud the microphone generates accordingly higher signals that not need the
same amount of gain.
For the hands free voice control to work as intended, any distortion must be eliminated. This is the
reason why microphones gain need to be adapted, especially in areas beyond normal office
conditions.
Likewise if used in quiet areas or for remote listening.
