Firecom FH-20 Quick Start Manual page 2

Proper Fit
When worn properly, this headset will provide significant hearing protection. If it is not worn
properly, the headset's effectiveness in reducing harmful noise is severely compromised.
• The length or vertical fit of the headset ear dome is adjusted by the headband. Adjust as
necessary to achieve a fit that ensures the headset ear dome completely covers the ear.
• When switching between right and left dress, rotate the mic boom in an upward direction
ONLY, as shown in the diagram below.
Rotating the mic boom in the wrong direction may damage the boom or wiring.
• For maximum comfort, wear the headset as far back on the head as possible, while ensuring
the ear dome still completely covers the ear. If discomfort is felt in the jawbone, you are
wearing the headset too far forward.
Microphone Placement
Place the microphone in front of the mouth and NO MORE than 1/8 " away from the lips as
shown in the diagram below. Placement of the microphone is CRITICAL for proper operation.
If the microphone is positioned incorrectly, you may experience a reduction in
volume and clarity of intercom and radio communication.
Headset Volume
Turn the intercom volume down. Preset each headset volume to the highest setting (full clock-
wise). Set the intercom volume to a level above the normal comfortable listening level, but at a
level which does not cause distortion. Reset the individual headset volume for best listening level.
Intercom Communication
The microphone on the FH-20 headset is only active while the black Push-To-Talk (PTT),
located on the ear dome, is depressed. To communicate on the intercom, press and hold the
black PTT while you are speaking. Release the black PTT when finished speaking.
Radio Transmit
The FH-20 will not transmit on the radio, it is for intercom communication ONLY!
Adjustable
headband
Push-To-Talk (PTT) button (black)
Adjustable headband
Volume control
Rotate the mic boom
ONLY in an upward
direction as shown.
No more than
1/8" from lips
Mic Muffs
The headset microphone is covered with a washable, replaceable foam mic muff. This mic
muff helps prevent the "pops" and "hisses" that can occur from speaking into a microphone
that is close to the mouth.
To clean or replace the mic muff:
1. Remove the o-ring.
2. Slip the mic muff off the microphone.
3. At this time, you can decide whether to clean
or replace the mic muff.
If you clean the mic muff, use a mild detergent, rinse it out well
and let it dry completely before re-installing it on the microphone.
4. Slide the mic muff on the microphone.
5. Install the o-ring on the mic muff to secure it.
Replacement mic muffs may be ordered from your local Firecom dealer.
Replacement Parts & Accessories
Description
300 Ohm Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0008-00
Acoustic Foam Set, 3 pieces (internal) . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0027-00
Boom Assembly (flex) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0015-00
Cloth Covers (a dozen pairs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0003-00
Coil Comm Cable (single plug) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0018-10
Ear Seals - Standard (pair) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0012-00
HE-150, 15 foot Headset Extension Cord . . . . . . . . . . . . . . . . . . . . . . . . .108-0675-00
Headset Hanger Hook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0676-00
Mic Muffs with O-Rings (dozen) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0004-00
PTT - Black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108-0010-00
Volume Control, Potentiometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151-0001-00
Volume Control, Knob . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .551-0001-00
Specifications
Headsets
Sensitivity . . . . . . . . . . . . . . . . . . . . . . 104 dB re .0002 microbar @ 1000 Hz, 1 mW
Frequency Response . . . . . . . . . . . . . . . . . . . . 100-17,000 Hz +5 dB in 6 cc coupler
Impedance . . . . . . . . . . . . . . . . . . . . . 600 ohms nominal, 150 to 1200 ohm source
Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2 oz.
Noise Reduction Rating (NRR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 dB
Microphone
DC Bias Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16 volts, not polarity sensitive
Source Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 to 2200 ohms
Output Voltage . . . . . . . . . . . . . . . . . . . . . . 370 mV @ 114 SPL re .0002 microbar
Frequency Response . . . . . . . . . . . . . Optimized for speech clarity and noise reduction
Max. Amb. Noise Level . . . . . . . . . . . . . . . . . . . . . . . .125 dB SPL re .0002 microbar
Mic muff
O-ring
Mic boom
Part Number