9
voice message.  To turn the volume off, press the – button 
(A:11) for two seconds. This is conrmed by the message 
“radio volume off”. Press the + button (A:10) to switch this 
function back on.
Note! No radio communication can be heard when the 
volume is switched off.
Note! When the volume is switched off the other menus will 
not be available.
3.5 Channel (radio frequency)
Press the + button (A:10) or – button (A:11) to select  bet-
ween eight available channels. Each change is conrmed by 
a voice message.  See table H  Radio channel frequencies.
3.6 VOX (voice-operated transmission)
VOX enables LiteCom to transmit automatically when sound 
above a certain level reaches the microphone. This allows 
radio transmission without pressing the PTT button (A:14).
Press the + button (A:10) or – button (A:11) to adjust the 
sensitivity of voice operated transmission. Each change is 
conrmed by a voice message. You can choose between ve 
levels or switch this function off. When the level is low it is 
easier to transmit. To switch this function off, press the – but-
ton (A:11) for two seconds. This is conrmed by the message 
“VOX off”. The PTT button (A:14) must now be used to 
transmit. Press the + button (A:10) to switch this function 
back on. Alternatively switch voice-operated transmission on 
or off by briey press the PTT button twice. A voice message 
conrms the current VOX setting.
The radio has a Busy Channel Lock Out (BCLO) function that 
prevents VOX operation if the channel is being used for other 
transmission. An audible tone indicates that the channel is 
already being used. Note! To activate the VOX function the 
speech microphone (A:8) must be very close to your mouth, 
1–3 mm (gure G). The user’s voice will be heard in the 
headset when the radio is transmitting.
3.7 Squelch (hiss reduction)
“Squelch” means that background hiss in the earphones is 
prevented when the incoming signal is below the set squelch 
level. Press the + button (A:10) or – button (A:11) to adjust 
the squelch level. Each change is conrmed by a voice 
message. You can choose between ve levels or switch this 
function off. A low squelch level may permit longer range. 
To switch this function off, press the – button (A:11) for two 
seconds. This is conrmed by the message “squelch off”. 
Press the + button
(A:10) to switch this function back on.
3.8 Sub channel (selective squelch )
Sub channel allows multiple groups of users to use the same 
channel without hearing other groups. When sub channel is 
active, an inaudible code will be transmitted with speech, and 
this code is used to ”open” the receiver of other users of the 
group. This allows multiple groups of users to use the same 
channel without hearing other groups. This product supports 
Continuous Tone Coded Squelch System (CTCSS), which me-
ans there are 38 codes which have been assigned the num-
bers 1–38 (table I, CTCSS). All communication on a channel 
can be heard if this function is switched off.
Note! When the sub channel function is switched on, all other 
incoming radio communication will be blocked. Press the + 
button (A:10) or – button (A:11) to select the sub channel. 
Each change is conrmed by a voice message. You can 
choose between 38 tones or switch this function off. To switch 
this function off press the – (A:11) button when sub channel 1 
is selected, or press the + (A:10) button when channel 38 is 
selected. This is conrmed by the message “sub channel off”. 
Press the + button (A:10) to switch this function back on.
3.9 PTT (Push-to-talk)
Press and hold the PTT button (A:14) to transmit manually 
using the radio. PTT transmission works at any time, regard-
less of BCLO (Busy Channel Lock Out, see 3.6 VOX).
3.10 Reset to factory defaults
To restore the default settings the unit must rst be switched 
off. Then press and hold the + (A:10) and – (A:11) buttons 
at the same time while also pressing the (A:9) On/Off/Mode 
button. This is conrmed by the voice message “restore 
factory defaults”.
4. IMPORTANT USER INFORMATION
Caution! The noise reduction may be lower when eyeglas-
ses, goggles or respirator straps are worn between the 
sealing surface of the earmuff cushions and the sides of the 
wearer’s head. For best noise reduction, select eyeglasses or 
goggles that have thin, at temples or straps which will mini-
mize interference with the seal of the earmuff cushions. Pull 
long hair back to the extent possible and remove other items 
that may degrade the earmuff seal such as pencils, hats, 
jewelry or earbuds. Do not bend and reshape the headband 
as this will cause a loose t and allow sound leakage.
Warning! These hearing protectors help reduce exposure to 
hazardous noise and other loud sounds. Misuse or failure to 
wear hearing protectors at all times when exposed to hazar-
dous noise may result in hearing loss or injury. This product 
contains metallic components that may increase electrical 
hazards. For proper use, see supervisor, Fitting Instructions, 
or call 3M Technical Service (In U.S.A. call 1-800-243-4630. 
In Canada, call 1-800-267-4414)
5. MAINTENANCE (gure J)
5.1 Removing/replacing ear cushions
(J:1) Slide your ngers under the edge of the ear cushion and 
pull straight out.
(J:2) Insert a new ear cushion by pressing until it snaps into 
place.
5.2 Care and Cleaning Instructions
•  Follow recommended care and cleaning instructions in 
order to maintain best noise reduction and function.
•  Wash outside of earmuffs only. Use mild soap and water. 
Do not immerse in water. Remove cushions or liners which 
have become damp and allow them to dry before reinstalling.
•  Do not clean with solvents such as alcohol or acetone, or 
EN