Refer to Fig. 8
Adjustment of Mic Gain, VR-1 and Noise Reduction Control, VR-2
In some aircraft it may be necessary to adjust both the Microphone gain control and the Noise Reduction
control.
Microphone output levels vary for different brands of headsets and for best results, mixing headsets is not
recommended. Headset microphones with high outputs can result in some background noise being heard
and it will be necessary to adjusted VR-1 to eliminate the amount of sound heard by the microphones.
Some headset manufactures* include a microphone gain control on the microphone. This gain adjustment
should be turned to the lowest setting for best results. Refer to the headset manual for the location of the
adjustment.
If background noise is still heard, VR-2 the Noise Reduction Control and be increased. When adjusting VR-2, at a point about
3/4 rotation, a sharp drop off of audio will be heard. This is the maximum noise location on the pot, back up slightly for proper
adjustment.
High Noise Environment
It has been found that in aircraft such as open cockpit airplanes, wind passing over the microphone and high engine power set-
tings such as take off and climb will produce a popping sound in the intercom. For wind noise, it is recommended that a wind
muff be used on the microphone. High engine power settings are a bit more difficult to deal with and may be reduced by adjust-
ing the microphone level control for the lower setting. During normal cruise power setting, there should be no outside noise com-
ing through the intercom.
Communication Radio Line Balance
When toggling the Pilot/ISO switch, a difference in the radio audio level may be heard. To correct this level difference, a level
balance pot,
VR-4
can be adjusted to set the audio level. Locate VR-4 and while listening to the communication radio audio
through the PILOTS headphone position, toggle the PILOT/ISO switch. Adjust VR-4until a even audio level is heard in both the
PILOT and ISO position.
Cellular Phone Interface
The Cell Phone interface includes a microphone level adjustment to provide the proper audio level to the cellular phone micro-
phone audio level. The factory setting should be correct for most phones and can be verified by making a call and noting the
speech quality on the called phone. If the audio is too low or clipping is heard, adjust VR-3 for the proper audio level.
After the adjustments are set and before closing the case, check to ensure that no wires are pinched or broken. Reassemble the
two parts of the case and tighten the two screws in the bottom of the case.
Service
With your new FlightTech ITC-404SP intercom properly installed, you will enjoy many years of trouble free operation. In the
event of a problem and after checking the obvious, fuse, jacks or wiring, you should contact the FlightTech Intercom Technical
Support center for suggestions or returning the intercom for repair.
The FlightTech phone numbers are located on the back cover of this manual.
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Summary of Contents for ITC-404SP
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