Comtek M-216 User manual

M-216 OPERATOR’S MANUAL
357 West 2700 South • Salt Lake City, Utah 84115 • Phone: [phone] • Fax: [phone] • http://www.comtek.com
M-216
Wireless
Microphone
Transmitter

INTRODUCTION
Page 1
The M-216 wireless microphone transmitter offers the ultimate
performance and versatility for assistive
listening, language interpretation,
tour guide presentations, personal
cueing, and for other personal remote
transmission situations.
The M-216 incorporates the latest digital
and analog technologies to produce low
residual noise, wide dynamic range,
and extended frequency response
rendering the most natural sound
possible from a wireless microphone.
The transmitter’s microcontroller
automatically sets the modulation deviation,
companding or non-companding audio
processing,andtheEQwhencorresponding
channels are selected. Because of this
comprehensivefeature,this
versatiletransmitter cantransmit
on 19 high fidelity channels and
38 standard channels ensuring
compatibility with receivers
conforming to regulations
regarding Low Power Radio Service
(LRPS) transmissions in the 216-217 MHz band
under Part 95 of the FCC regulations.
M-216
Wireless
Microphone
Transmitter

Setup
a. Check to ensure that the M-216 transmitter’s radio frequency channel is
the same as the associated COMTEK receiver’s channel. (Channels are
indicated by the rotary channel selector switches on the back of the
transmitter. See page 3.)
b. Open the battery door cover on the transmitter (see page 4) and
insert a new nine volt alkaline battery (Eveready E522 or equivalent). This
type of battery will offer up to 40 hours of operation. Replace the battery before
every use if the demand for fail-safe operation outweighs battery cost. The use of
carbon batteries is not recommended.
NOTE: If a rechargeable battery is to be used, ensure that it has been
allowedto charge atleast twelve hoursto bring ittofullcharge (seepage7
forbatterychargerinstructions).
c. Connect the microphone to the transmitter by inserting the microphone
plug into the receptacle on the top of the transmitter. The transmitter is
operating when the transmitter power switch is turned on and the battery
status/on indicator illuminates.
NOTE: The36-inch microphone cordalsofunctions as partof the
transmitter’santenna system. For optimum performance,thiscord
shouldbefullyextended. Coilingorbunchingthemicrophone
cordmay reduce therange of thetransmitter. Thetransmitter
shouldbecarried by thesnap-onbeltclip(included)orina pocket
orbelt-clip pouch.
d. In a situation where an extremely loud voice or a very soft voice is used, it
is necessary to adjust the audio input gain control while observing the audio
“voice” level modulation indicator.Afull bright LED indicates full audio
compression at 100% modulation. For best performance, the audio input
gain should be adjusted for some low level LED luminescence during
normal audio levels with occasional full bright peaks indicating 100%
modulation.
M-216 OPERATING INSTRUCTIONS
Page 2

Page 3
Frequency Selection (216-217 MHz)
The M-216 transmitter can operate on one of 57 available channels between
216 MHz and 217 MHz. COMTEK’s channel designations indicate both
standard narrow-band channels and high-fidelity, wide-band companded
channels. Channels 1-40 are narrow-band channels (5 kHz deviation)
offering compatibility with other manufacturers’ receivers such as the
Phonak MicroEar. Channels 41-60 are high-fidelity, wide-band companded
channels (10 kHz deviation) for use with COMTEK transmitters. COMTEK
transmitters automatically transmit the proper modulation when set to
channels 1-40 for narrow-band or 41-60 for wide-band companded channels.
After you have determined the channel on which
you are going to operate, position the two rotary
switches to indicate the channel. The left rotary
switch is for tens and the right rotary switch is
for ones. To select channel 41 (216.0250 MHz),
position the left rotary switch to point to 4 (X10),
and position the right rotary switch to point to 1 (X1).
Refer to frequency charts on pages 9 and 10 for selectable frequencies.
Multiple Channel Operation
When multiple transmitters are broadcasting in the same immediatearea
(within 100 feet), the RF signals will “mix” together generating additional
signals. Ifthese productfrequencies aretooclose toafrequency whichyou are
using,you will experienceintermodulation interference. This conditionis
commontoall radioreceiversto someextent.
Simultaneous operation of more than three channels requires frequency
coordination to avoid intermodulation interference, which could result in
poor or unusable performance.
To avoidthis typeofinterference,youshould selectfrequenciesfrom oneofthe
standard groups (see frequency group charts on page 10), or use COMTEK’s
frequencyselectionsoftware(www.comtek.com/software.htm)todetermine
appropriatefrequencies or contact COMTEK to obtain a free copy.
M-216 OPERATING INSTRUCTIONS

Low Battery Indicator
The LED on the top of the transmitter
indicates the status of the battery as
well as indicating that the unit is turned
on. When turned on, the LED illuminates.
If the battery is low the green LED will
blink rapidly to warn you that the battery
will soon be dead. Replace a low battery
immediately.
Battery Removal / Replacement
M-216 OPERATING INSTRUCTIONS
Page 4
Pull back battery door latch and allow battery
cover door to spring open. To remove battery,
simplymanipulate the bottom ofbatteryout of
thecompartmentand remove.
To insert battery, face battery
with negative terminal in line with
large hole in battery compartment,
press battery into compartment and close
battery door until it snaps shut. Note: It is not
possible to put battery in backwards.
Battery indicator LED

Page 5
M-216 OPERATING INSTRUCTIONS
Auxiliary Audio Input Operation
The M-216 transmitter may transmit from a
variety of audio sources such as tape and C.D.
players, TV and VCR’s, or any audio device
having an auxiliary or line level audio output.
The auxiliary input cable supplied with the
M-216transmitter(CB-36ST) will operate
with any device having a mini 3.5 mm
jack, stereo or mono, and with line level or
earphoneleveloutput.
To accommodate a variety of specialty
applications, auxiliary input cables
with RCA phono plug, 1/4” audio
phone plug, and XLR connectors are
availablefrom COMTEK.
Setup
a. Plug the micro-mini
screw-lock whip antenna
into the top centerjack
(mic/ant.)oftheM-216
transmitter. Thewhip
antenna should be in a
vertical position away from
any metallic objects to insure
maximumrange performance.
b. Connect the proper auxiliary input cable to the
audio source. Connect the right-angle mini plug end of the
auxiliary input cable in the “AUX” input jack of the M-216 transmitter.
Note: Checkto ensure thatthe audio sourceis a linelevel, earphone level,
orfixedAUXleveloutput.
(continued)

Page 6
Beltclip installation
M-216 SNAP-ON BELT CLIP (Included)
Belt clip removal
c. Turn on the transmitter with program from the audio source being fed to
the transmitter. Observe the audio “voice” level modulation indicator. Afull
bright LED indicates full audio compression at 100% modulation. For best
performance, the audio input gain should be adjusted for some low level
LED luminescence during normal audio levels with occasional full bright
peaks indicating 100% modulation.
d. When using the auxiliary audio input with the microphone plugged into
the transmitter, priority should be given to the microphone gain adjustment.
The mixing balance between the auxiliary audio and the microphone should
be made with the volume control of the auxiliary audio source.
Note:The optional microphone mute switch only affects the
microphone. It does not affect the auxiliary audio input.
M-216 OPERATING INSTRUCTIONS
STEP1:
Hook belt clip
retaining lip over
front case ridge.
STEP2:
Rotate belt clip down onto case. Apply
pressure on both sides of clip, snapping
clip retainers into slots.
Clip retainer
Retainer slot Belt clip removal indent
Flex out and pull down with your
thumb or a large coin (quarter) to
unsnap belt clip from case.

Page 7
Battery Charge
To charge the M-216 with the NBC 9-2C charger:
1. Make sure that a Ni-MH or Ni-Cad rechargeable battery is used.
(Alkalinebatteries must not be chargedwith the NBC 9-2C charger.)
2. Make sure the M-216 is turned OFF.
3. Note that the red charging indicator on the NBC 9-2C should turn on
when the charger output cord is plugged into the AUX input
receptacle on the transmitter.
4. Charge the battery for 12 hours to allow 12 hours of operation
when Ni-MH battery is used. Note that immediately after charging, the
battery will be warm. This is normal and not cause for alarm.
5. On stored COMTEK units, periodically open the battery compartment to
check for battery leakage. If a battery is leaking, it must be discarded,
and the battery compartment must be cleaned or returned to COMTEK’s
service department for repairs.
IMPORTANT
M-216 OPERATING INSTRUCTIONS

M-216 CONTROLS
!COMPANDAUTO/OFFSWITCH:This switch overrides
the automatic selection of the companded channels to
non-companded operation.
"CHANNELSWITCHES: These rotary switches
are set to the same channel as the receiver. Actual
frequency of operation must agree with the
receiver.
(See page 10 for frequency selection chart.)
#BATTERYCOMPARTMENT: The
battery compartment features a hinged
battery cover and an alignment system that
ensures proper battery polarity. Battery
installation and removal is facilitated by simply
manipulating the bottom of the battery.
$AUXILIARY AUDIO INPUT JACK:
Allows transmitter to use line level, earphone
level, or fixed AUX as an audio source.
%AUDIO“VOICE”MODULATIONINDICATOR:
This indicator is used in making adjustment with the
Audio Input Gain Control.
&MIC / ANTENNA JACK: This jack accepts an
electret type microphone having a 36” long cord with
a micro-mini 2.5mm mono plug. This jack is also used
for the R.F. output for the screw-in whip antenna when
the auxiliary audio input is used.
'POWER/BATTERYSTATUSINDICATOR: This LED indicator will illuminate
continuously when the unit is on, indicating normal operation. When the battery voltage
drops below 6 volts, the LED will flash rapidly, indicating that a new battery is needed.
(OPTIONALMICMUTESWITCH: This switch turns off the microphone without
turning off the transmitter carrier.
)AUDIOINPUTGAINCONTROL: This is a microphone and AUX level input gain
control. This control is used with the “Voice” modulation indicator.
*ON / OFF SWITCH: This switch turns the transmitter on and off.
Page 8

Page 9
M-216 FREQUENCY CHART
CHANNEL
(SWITCH POSITION) FREQUENCY
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
216.0125 MHz
216.0375 MHz
216.0625 MHz
216.0875 MHz
216.1125 MHz
216.1375 MHz
216.1625 MHz
216.1875 MHz
216.2125 MHz
216.2375 MHz
216.2625 MHz
216.2875 MHz
216.3125 MHz
216.3375 MHz
216.3625 MHz
216.3875 MHz
216.4125 MHz
216.4375 MHz
216.5125 MHz
216.5375 MHz
216.5625 MHz
216.5875 MHz
216.6125 MHz
216.6375 MHz
216.6625 MHz
216.6875 MHz
216.7125 MHz
216.7375 MHz
216.7625 MHz
216.7875 MHz
216.8125 MHz
216.8375 MHz
216.8625 MHz
216.8875 MHz
216.9125 MHz
216.9375 MHz
216.9625 MHz
216.9875 MHz
Narrow-Band Channels; 5 kHz dev.
For use with COMTEK and other manufacturers
(Educational Standard)
High-Fidelity Channels; 10 kHz dev.
For use with COMTEK equipment only
(Companded)
216.0250 MHz
216.0750 MHz
216.1250 MHz
216.1750 MHz
216.2250 MHz
216.2750 MHz
216.3250 MHz
216.3750 MHz
216.4250 MHz
216.5250 MHz
216.5750 MHz
216.6250 MHz
216.6750 MHz
216.7250 MHz
216.7750 MHz
216.8250 MHz
216.8750 MHz
216.9250 MHz
216.9750 MHz
216.0250 MHz
216.0750 MHz
216.1250 MHz
216.1750 MHz
216.2250 MHz
216.2750 MHz
216.3250 MHz
216.3750 MHz
216.4250 MHz
216.5250 MHz
216.5750 MHz
216.6250 MHz
216.6750 MHz
216.7250 MHz
216.7750 MHz
216.8250 MHz
216.8750 MHz
216.9250 MHz
216.9750 MHz
41
42
43
44
45
46
47
48
49
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
71
72
73
74
75
76
77
78
79
70
FREQUENCYCHANNEL
(SWITCH POSITION)

Page 10
CHANNEL FREQUENCY
1
9
15
24
31
36
216.0125MHz
216.2125MHz
216.3625MHz
216.5875MHz
216.7625MHz
216.8875MHz
GROUPA
216 MHz
WIDE-BAND
FREQUENCY GROUPS
For COMTEK
equipment only
(10kHzdeviation)
M-216M-216
216 MHz
NARROW-BAND
FREQUENCY GROUPS
CompatiblewithCOMTEK
andother manufacturers
(5 kHzdeviation)
CHANNEL FREQUENCY
4
10
14
32
35
40
216.0875MHz
216.2375MHz
216.3375MHz
216.6875MHz
216.8875MHz
216.9875MHz
GROUPB
CHANNEL FREQUENCY
3
5
12
22
38
216.0624MHz
216.1125MHz
216.2875MHz
216.5375MHz
216.9375MHz
GROUPC
CHANNEL FREQUENCY
17
23
30
34
39
216.4125MHz
216.5625MHz
216.7375MHz
216.8375MHz
216.9625MHz
GROUPD
CHANNEL FREQUENCY
41
44
51
55
60
216.0250MHz
216.1750MHz
216.5250MHz
216.7250MHz
216.9750MHz
GROUP1
CHANNEL FREQUENCY
42
49
53
58
216.0750MHz
216.4250MHz
216.6250MHz
216.8750MHz
GROUP2
CHANNEL FREQUENCY
43
46
51
57
216.1250MHz
216.2750MHz
216.5250MHz
216.8250MHz
GROUP3
CHANNEL FREQUENCY
44
47
54
59
216.1750MHz
216.3250MHz
216.6750MHz
216.9250MHz
GROUP4

Page 11
OptionalAccessories
1. NBC 9-2C Battery charger
2. NH9-150 Rechargeable batteries
3. P1 Universal pouch
4. BC-216 Snap-on belt clip
(supplied with M-216)
5. LW-216 Whip antenna
(supplied with M-216)
6. PSC-HM Headworn
unidirectional electret
microphone
7. HH-185 Hand held microphone
boom adaptor
8. TM-10 Conference table
microphone adaptor
9. SM-185 Unidirectional
electret condenser
microphone
Auxiliary Audio Input Cords
10. CB-36 STM Stereo mini 3.5mm
(supplied with M-216)
11. CB-36 RCA Phono plug
(optional)
12. CB-36 ST1/4 Stereo 1/4”
(optional)
13. CB-36 XLR XLR-F 3 pin connector
(optional)
M-216 OPTIONAL ACCESSORIES

M-216 SPECIFICATIONS
Page 12
Audio Input:
• Microphone input impedance for electret
type microphone - 3000 ohm
• Aux/Line input impedance - 10 k ohm at
0 dB nominal
Connectors:
Microphone-Micro-minimono 2.5mm
Auxiliary - Mini stereo 3.5mm
Audio: Tip and sleeve
Battery Charging: Tipandsleeve
Controls and Indicators:
• Synthesized channel selection switches
• Power On/Off switch
• Optional microphone muting switch
• Audio input gain control
• Power/Battery status indicator
• Audio (voice level) modulation indicator
• Companded auto/off switch
Frequency Response:
80 Hz to 10 kHz
Audio Distortion:
Less than 1% at 80% modulation
Modulation Limiter:
Soft compressor with 30 dB linear overload
protection, attack time - less than 1 ms,
recovery time - 10 ms
Modulation:
• 5 kHz deviation Ch. 1-40 (non-companded)
• 10 kHz deviation Ch. 41-60 (companded)
Operating Radio Frequency:
ity: 57 synthesized channels in the 216-217 MHz
LPRS band under FCC part 95
Out-of-Band Emissions:
Better than 45 dB below carrier
R.F. Stability:
20 ppm XTL controlled
Digitally synthesized
RF Power Output:
10 mW to antenna system
Antenna System:
Bodywornmicrophonecord, or
loaded whip plugged directly
intomicrophone connector when
auxiliary input is used
Current Drain:
13 mA constant current
Battery:
• 9 volt alkaline Eveready 522
or equivalent for up to 40 hours
of operation
• 9 volt Nickel-Metal Hydride
rechargeable battery for up to
12 hours of operation
Dimensions:
1 1 /16" x 2 1 /4" x 3 1 /2"
(27 mm x 57 mm x 89 mm)
Weight:
5 ounces (140 grams)
FCC Compliance:
Certification under Part 95
NOTE: Specifications subject to
change without notice or
obligation

357 West 2700 South • Salt Lake City, Utah 84115
Phone: [phone] • Fax: [phone]
Web Page: http://www.comtek.com
M-216 WARRANTY AND SERVICE
Warranty
COMTEK warrants this product to be free from defects in workmanship and
material under normal use and conditions for a period of one year from date
of original purchase. Items such as batteries, neckloops, and cords are not
covered by the warranty. Damage due to misuse, ill treatment and
unauthorized modification and repairs are not covered by this warranty. COMTEK is
not liable for consequential damages arising out of any failure
of the equipment to perform as intended. COMTEK shall bear no responsibility or
obligation with respect to the manner of use of any equipment sold by it.
COMTEK SPECIFICALLY DISCLAIMS AND NEGATES ANY WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
OF SUCH EQUIPMENT INCLUDING, WITHOUT LIMITATION, ANY
WARRANTY THAT THE USE OF SUCH EQUIPMENT FOR ANY PURPOSE
WILL COMPLY WITH APPLICABLE LAWS AND REGULATIONS.
ServicePolicies
Warranty repairs must be done by COMTEK. Only factory technicians are
authorized to perform warranty service on the M-216 transmitter. Before
returning the M-216 for service, a Return Authorization Number should
be obtained from the service department by calling 1-800-496-3463 or
1-801-466-3463. Return the unit to the factory with the original or comparable packing.
COMTEKwill pay for insurance andground return shipping costs in the United States
for all warranty service.
© 2001 COMTEK®All rights reserved.
Print Release Date 08-05-2001-B