Williams Sound MOD 112 Assembly instructions

Williams Sound ®
Helping People Hear
SoundPlus®WIR TX800
Two Channel Infrared System
Large Area Infrared Listening System
Modulator Model MOD 112
Emitter Model WIR TX8
Receiver Models WIR RX5, RX6
Installation
Guide &
User
Manual
MAN 084D

SOUNDPLUS®WIR TX800 INFRARED LISTENING SYSTEM,
TWO–CHANNEL INFRARED LISTENING SYSTEM
INSTALLATION GUIDE AND USER MANUAL
Contents Page
SYSTEM OVERVIEW 4
INSTALLATION PROCEDURES 6
STEP 1: TX8 EMITTER SETUP
STEP 2: TX8 POWER WIRING
STEP 3: BASEBAND CABLE CONNECTION
STEP 4: MOD 112 MODULATOR SETUP
STEP 5: TESTING THE SYSTEM
CONTROLS AND FEATURES 14
MOD 112 FRONT PANEL
MOD 112 REAR PANEL
TX8 EMITTER REAR PANEL
RECEIVER INSTRUCTIONS 19
TROUBLESHOOTING 21
WARRANTY 22
SPECIFICATIONS 23
NOTE: TAKING A FEW MINUTES NOW TO READ THESE INSTRUCTIONS WILL SAVE TIME AND ENSURE PROPER
SYSTEM OPERATION.
Williams Sound ®
Helping People Hear
3

Williams Sound ®
Helping People Hear
4
SYSTEM OVERVIEW
The Williams Sound WIR TX800 System consists of a MOD 112 Modulator and one or more
TX8 Emitters which use invisible infrared (IR) light waves to broadcast speech or music to
wireless infrared receivers.
The MOD 112 accepts a variety of audio inputs and sends 95 kHz and 250 kHz frequency
modulated signals to the TX8 Emitter via coaxial cable. The emitter emits invisible infrared
light into the listening area. Infrared receivers detect the transmission and convert the light
signals back into audio signals.
The system is designed to transmit high quality audio for hearing assistance and language
translation applications. Because the system uses infrared light for transmission, it is not
affected by interference from radio equipment and does not interfere with radio equipment.
No FCC license is required.
The TX8 Emitter is designed to distribute its power equally among the channels sent to it for
transmission. Thus, when only a single channel is present, the TX8 uses all its power to
broadcast the lone signal, achieving a coverage area of approximately 10,000 square feet
(930 square meters). When two signals are sent to the TX8 (as is the case when the MOD
112 is in Stereo mode or in Discrete mode when both channels are in use), the TX8 divides
its power among the two signals. This makes for a practical coverage area of about 3,767
square feet (350 square meters). This important principle is illustrated in Figure 3. Larger
areas can be covered with additional emitters.
The system can be used with a microphone as a stand-alone system, or can be connected to
an existing sound system. Infrared Systems cannot be used in bright sunlight because of
sunlight’s large amount of interfering infrared light.

Williams Sound ®
Helping People Hear
5
TX8 Emitter
MOD 112 Modulator
Baseband In
Baseband Out
Power Supply
120 VAC (US): TFP 016
230 VAC (CE): TFP 027
Power Supply
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
Power On
Indicator
(Visible From Below)
Baseband
Present
Indicator
(Visible From Below)
Phones
Infrared
Test Out
MOD 112 Two-Channel Infrared System Modulator Williams Sound
Power
CXR
Limit
Compress
Discrete
Stereo
Audio Mode Phones
CH1
CH2
CXR
-21 -18 -15 -12 -9 -6 -3 0 +3 [phone] +3 +6
5
0
1
2
3
46
7
8
9
10
CH 1 Level CH 2 Level
Channel 1 Channel 2
5
0
1
2
3
46
7
8
9
10
Power Supply
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
Baseband Signal
Power Supply
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
MOD 112 Modulator
Power Supply
120 VAC (US): TFP 016
230 VAC (CE): TFP 027
Baseband In
Baseband
Out
TX8 Emitter
TX8 Emitter
Phones
Infrared
Test Out
MOD 112 Two-Channel Infrared System Modulator Williams Sound
Power
CXR
Limit
Compress
Discrete
Stereo
Audio Mode Phones
CH1
CH2
CXR
-21 -18 -15 -12 -9 -6 -3 0 +3 [phone] +3 +6
5
0
1
2
3
46
7
8
9
10
CH 1 Level CH 2 Level
Channel 1 Channel 2
5
0
1
2
3
46
7
8
9
10
Baseband Out
Baseband In
FIGURE 1A: TYPICAL SYSTEM CONFIGURATIONS
FIGURE 1B: USING AN ADDITIONAL TX8 EMITTER FOR GREATER COVERAGE AREA.

Williams Sound ®
Helping People Hear
6
INSTALLATION PROCEDURE
INSTALLATION STEP 1: TX8 EMITTER SET-UP
SELECTING A MOUNTING LOCATION
The most important principle to understand when installing the TX800 system is that invisible infrared
light behaves just like visible light. It does not pass through opaque objects such as walls, curtains, or
people. It does pass through windows and door openings and can bounce and scatter off reflective walls,
floors, and ceilings. Therefore, the infrared emitter panels should not be concealed or covered, nor should
the infrared “eye” on receiver units be covered. Receivers work best with a clear line-of-sight to the
emitter panels.
The TX8 Infrared Emitter should not be installed outdoors, or where there is a lot of direct sunlight
indoors. Sunlight generates infrared interference. Certain types of high-efficiency lighting fixtures can also
generate interference at 95 kHz because they use high frequency modulation.
MOUNTING THE TX8 TO A WALL OR CEILING:
Step 1: Using the mounting plate (Figure 2A) as a template, mark the hole locations on the mounting surface
where the TX8 will be installed. See Page 7, Figure 2B for optional mounting positions.
Step 2: Locate the top mounting hole in the rear of the TX8 emitter. Gently screw the male end of the swivel
head on to the emitter. Tighten the swivel head tension screw: turn clockwise until the connection is secure.
Step 3: Screw the male end of the shaft into the female end of the swivel head. An additional shaft can be
added to create more distance between the wall/ceiling and Emitter.
Step 4: Place the plate cover snugly over the mounting plate. This will hide the screws after installation.
Step 5: Screw the male end of the mounting plate into the female end of the shaft. For suspended ceilings, screw
the female end of the shaft into the male end of the T-Bar clip. The mounting bracket is now installed on to
the TX8 Emitter.
Step 6: Position the TX8 Emitter and BKT 024 so the mounting plate lines up with the marked holes on the
mounting surface. Fasten the mounting plate to the surface using screws and wall anchors. Mounting
the TX8 to a Suspended Ceiling with Cross Tee: Fasten the T-Bar clip on to the desired Cross Tee.
Step 7: Position the TX8 Emitter to the desired angle: Begin by gently turning the tension screw (Figure 2A) counter
clockwise to release the swivel head. Adjust the TX8 to the desired angle. When the TX8 is in the desired
position, gently turn the tension screw clockwise until the swivel head is securely in place.
FIG. 2A: BRACKET 024 MOUNTING
TX8 Emitter Swivel Head
tension screw
Shaft
(optional) Shaft Plate Cover Mounting Plate
Mounting
Screws
(To Wall or Ceiling)

Williams Sound ®
Helping People Hear
7
ILLUMINATION PATTERNS
The infrared illumination pattern from a single emitter is cone-shaped, with a 50° angle. The
horizontal and vertical patterns are identical. Figures 3, 4, and 5 show top and side views of
coverage patterns.
TX8
25°
25°
75 ft. (23 m)
135 ft. (41 m)
67 ft. (20 m)
37 ft. (12.5 m)
Two Channel Mode
Practical coverage
area is approx. 3,767
sq. ft. (350 sq. m)
Single Channel Mode
Non-reflective
coverage area is
approx. 10,000 sq. ft.
(930 sq. m)
FIGURE 3: IR PATTERNS, SINGLE EMITTER INSTALLATION
TX8 TX8
TX8TX8
FIGURE 4: MULTIPLE EMITTERS INSTALLED TOMAXIMIZE COVERAGE
FIG. 2B: WALL OR CEILING MOUNT
Figure 2a: Mounting the TX8 on
to a wall with the BKT 024.
Tip: To keep the TX8 level, rotate
the tension screw (Fig. 2A) so it
rests on top of the bracket.
Figure 2b: Mounting the TX8 on
to a ceiling with the BKT 024.
A. B.

Williams Sound ®
Helping People Hear
8
These patterns are the direct radiation pattern. The infrared radiation does not drop to zero outside the
illustrated patterns; it decreases. It still may be useable at a greater distance, depending on receiver
sensitivity and the reflection characteristics of the room.
Infrared light reflects off most surfaces and scatters, increasing the coverage area. Rough surfaces tend
to absorb infrared light, minimizing reflections, and limiting coverage to the direct illumination pattern.
It’s helpful to think of the IR emitter as an invisible floodlight. You want to aim it so listeners are
“flooded” with infrared light.
It’s desirable for the illumination patterns to overlap when multiple emitters are used. Placing the
emitters high above the audience (15–30 ft./4-8m) and aiming them slightly downward (5°–15°) will
ensure the longest “throw” of the infrared beam. Angling the emitter inward towards the center of the
room also increases the coverage of the seating area.
Remember: opaque objects block infrared light. Thus, emitters cannot be concealed behind opaque
walls, curtains, etc. Neither should emitters be used in areas of extreme high or low temperatures,
humidity, or chemical environments.
COVERAGE AREA
The TX8 Emitter is designed to distribute its power equally among the channels sent to it for
transmission. Thus, when only a single channel is present, the TX8 uses all its power to broadcast the
lone signal, achieving a coverage area of approximately 10,000 square feet (930 square meters). When
two signals are sent to the TX8 (as is the case when the MOD 112 is in Stereo mode or in Discrete mode
when both channels are in use), the TX8 divides its power among the two signals. This makes for a
practical coverage area of about 3,767 square feet (350 square meters) or about 350 average theater
seats. This important principle is illustrated in Figure 3.
If you’re not getting sufficient coverage with a single, properly installed emitter panel, you’ll need to add
additional TX8 Emitters to achieve full coverage of your listening area.
Figures 3, 4, and 5 illustrate infrared light patterns and recommended emitter locations. In listening areas
up to 3,767 square feet (350 sq. m.) , the TX8 Emitter panel should be installed on the front wall of the
listening area in a position to flood the listening area. It must be above the audience to permit a direct
line of sight between the emitter and people wearing receivers when the people are standing or sitting.
Listening areas of more than 3,767 square feet (350 sq. m.) will require two or more TX8 Emitters for
complete coverage. Place one emitter panel on the left side of the front wall and the other on the right
hand side. For extremely large venues, additional TX8s should be located to maximize coverage
throughout the listening area.
120'
SCREEN
30'
STAGE
6'
Center Of Emitter Beam
TX8
FIGURE 5: SIDE PERSPECTIVE

Williams Sound ®
Helping People Hear
9
INSTALLATION STEP 2: TX8 POWER WIRING
FOR U.S. APPLICATIONS:
The TX8 Emitter is supplied with a low-voltage wall transformer power supply
(TFP 010). Two-conductor 18 ga. power cord is included with the emitter.
FOR APPLICATIONS OUTSIDE THE U.S. REQUIRING 240 VAC MAINS SUPPLY:
Use the wall transformer power supply, model TFP 027.
Secondary Specifications: 24 VAC, 35 VA, 50/60 Hz.
WARNING: POWERLINE VOLTAGE MUST NOT FALL BELOW 94V, OR
SYSTEM PERFORMANCE WILL BE GREATLY REDUCED!
DO NOT CONNECT THE POWER SUPPLY TO AC POWER YET!!!
Step 1: Determine the length of power cord needed to reach from the transmitter to the AC
wall outlet where the power supply will be plugged in. If power cord length will
exceed 200 feet (61 m), heavier gauge wire will be required. Use the table below.
Make sure the power supply is not plugged into AC power yet!
Cable Length Required Minimum Wire Gauge
Up to 10 feet (3 m) 22 gauge
Up to 5 feet (23 m) 20 gauge
Up to 200 feet (61 m) 18 gauge
Up to 500 feet (152 m) 16 gauge
Up to 1,000 feet (305 m) 14 gauge
One end of the power cord has a 3-pin Molex connector, the other end is bare. Cut
the bare end of the power cord to length. Strip this end down the middle
approximately
1 inch, then strip both of the resulting strands about 1/8 inch. Install the crimp-on
spade terminals supplied and connect these to the screw terminals on the Power
Supply (TFP 010). Polarity is not important since AC power is being used.
Step 2: Plug the 3-pin Molex connector into the TX8’s Power In connector.
Step 4: Plug in the Power Supply last.
The Power Indicator LED on the right side of the bottom panel (visible from
directly underneath) glows when the TX8 is on.
Note: The TX8 transmits when an audio signal is present, and will shut off when no
signal is present for about 30 minutes. This auto shut-off feature preserves the life
of the infrared LEDs and reduces power consumption.
This system is designed for Class 2, low-voltage wiring. Always follow local electrical codes
when doing low voltage wiring.
!! IMPORTANT WARNING !!
SHORTING THE POWER SUPPLY OUTPUT TERMINALS WILL BLOW A
NON-REPLACEABLE INTERNAL FUSE, DESTROYING THE POWER SUPPLY UNIT!

Williams Sound ®
Helping People Hear
10
INSTALLATION STEP 3: BASEBAND CABLE CONNECTION
IFYOU ARE USING ONE EMITTER:
Step 1: Determine the length of RG-58 coaxial cable needed to reach from the emitter to
the modulator unit. The modulator is usually located with the other sound
equipment to simplify audio connections. 100 feet (30 m) of coaxial cable is
included with each emitter. You will need to cut it to length. Additional RG-58
coax can be added. Make sure you leave some slack at each end.
Step 2: Install BNC connectors on each end of the cable. (See Figure 7.)
Step 3: Connect the Baseband cable to the Baseband Out jack on the MOD 112 modulator
and to the Baseband In jack on the TX8 Emitter. (See Figures 6 and 8.)
IFYOU ARE USING MORE THAN ONE EMITTER:
Step 1: Determine the length of coaxial cable needed to reach between the emitters. 100
feet (30 m) of coaxial cable is included with each emitter. You will need to cut it to
length. Additional RG–58 coax can be added. Make sure you leave some slack at
each end.
Step 2: Install BNC connectors on each end of the cable. (See Figure 7.)
Step 3: Connect the baseband cable from the Baseband Out Jack on the first emitter in the
chain (the one connected to the MOD 112 Modulator) to the Baseband In jack on
the next TX8 Emitter in the chain. Use the cable clamps and screws provided to
secure the cable. The coax can also be routed through conduit before attaching
BNC connectors. You can chain as many emitters together as you need. Remember
that each emitter needs its own TFP 010 power supply.
MOD 112 Modulator
Power Supply
120 VAC (US): TFP 016
230 VAC (CE): TFP 027
Baseband Out
TX8 Transmitter
Baseband In
Baseband Out
Baseband In
To Additional
TX8 Transmitters
Baseband Out
Channel
(kHz)
95 250
24
Power On
CNC
Mounting
Template
Power Supply
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
TX8 Transmitter
24
Power On
CNC
Mounting
Template
Power Supply
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
Model WIR MOD112 Two-Channel Infrared System Modulator
FIGURE 6: TX8 EMITTER WIRING DETAIL

Williams Sound ®
Helping People Hear
11
Nut Secured Into
Plug Assembly
50 ΩBNC Plug Connector
Plug
Assembly
Contact
Clamp
Grooved Side
Gasket
Washer
Nut
Gasket (note groove)
Washer
Nut
Cable Jacket
7.92 mm (±.25)
.312 in. (±.01)
Clamp positioned
against Cable Jacket
Clamp Braid folded
over Clamp and trimmed
Clamp Collar
3.96 mm (±.25)
.156 in. (±.01)
Dielectric
Dielectric
Contact soldered to conductor
and bottomed on dielectric
Plug Assembly
Gasket (Ref.)
Contact Assembly
inserted into Plug
Assembly
7B
7C
7D
7E
7F
7G
7H
FIGURE 7: BNC CONNECTOR ASSEMBLY
ASSEMBLY PROCEDURE
The BNC Connector consists of a plug assembly, a
contact, a clamp, a gasket, a washer, and a nut.
1. Slide nut, washer and gasket over cable end;
then strip outer cable jacket using the
recommended strip-length dimension in fig. 7b.
2. Slide clamp over cable braid and position it
against the cable jacket. After clamp is
properly positioned, comb out the braid.
3. Fold cable braid over the clamp and trim it so
that it is positioned against the clamp collar.
See figures 7c and 7d.
4. Using the dimension in figure 7e, strip
dielectric to expose the center conductor. If
applicable, tin the center conductor.
5. Solder contact to the conductor (using standard
soldering techniques), making sure contact is
bottomed on cable dielectric. See figure 7f.
DO NOT allow a hot soldering iron to touch
cable dielectric. Certain cable dielectric
materials, such as polypropylene, will expand
if they come in contact with a hot soldering
iron.
6. Insert contact into plug assemble until contact
snaps into place. See figure 7g.
7. Thread nut into plug assembly until it is secured.
Recommended cable clamp tightening torque is
2.8–3.4 N•m [25-30 in.-lb.], using a 7/16"
wrench. See figure 7h.

Williams Sound ®
Helping People Hear
12
INSTALLATION STEP 4: MOD 112 MODULATOR SETUP
LOCATION
The Modulator is usually located with the sound system amplifier or mixer for easy access to
an audio input signal. For portable systems, the modulator can be placed near the emitter or
in another convenient location. (The SS-6 Stand Kit is available for portable systems.)
POWER CONNECTION FOR U.S. APPLICATIONS:
Step 1: Connect the power supply to the 3-pin Molex connector located on the rear of the
MOD 112. (See Figure 8.)
FOR APPLICATIONS OUTSIDE THE U.S. REQUIRING 240 VAC MAINS SUPPLY:
Use the wall transformer power supply, model TFP 027.
Secondary Specifications: 24 VAC, 35 VA, 50/60 Hz.
Step 2: Plug the power supply into an AC outlet.
BASEBAND CABLE CONNECTION
The MOD 112 drives one emitter. The TX8 repeats the baseband signal, so any number of
emitters can be used. The modulator outputs CANNOT be split with CATV splitters.
AUDIO CONNECTION
The MOD 112 accepts audio signals from industry-standard low impedance microphones,
balanced lines, and unbalanced lines.
MICROPHONE
An industry standard 3-pin male connector is used. Pin 1 is the shield and pins 2 and 3
are audio. Power for condenser microphones is supplied according to DIN 45596.
BALANCED LINE
A 1/4 inch Tip-Ring-Sleeve (3 conductor) phone plug is used. The three-pin connectors
are used for the mic input only.
UNBALANCED LINE
A 1/4 inch Tip-Sleeve (2 conductor) phone plug is used.
Model WIR MOD112 Two-Channel Infrared System Modulator
Accessory
Power: 24 VAC,
50-60 Hz, 10VA
Williams Sound Corp., Minneapolis, MN USA
Balanced
Mic (XLR)
Bal or Unbal
Line (1/4")
Ch 1 Audio Input Ch 2 Audio Input
Baseband
Output
Baseband
Input
50 Ohms 50 Ohms
Baseband Output Connection
Connect to TX8 here using
RG-58 cable and BNC connector.
Power Connection
Power Supply
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
FIGURE 8: MODULATOR WIRING DETAIL

Williams Sound ®
Helping People Hear
13
8 Ωspeaker lines can be connected to the balanced line input. It is usually better NOT to
connect to the sleeve of the plug and thus avoid creating a ground loop.
A 25 V, 70 V, or 100 V speaker line can be connected to the balanced line input using an
appropriate attenuator. “T” pads made with resistors yield better fidelity than speaker
matching transformers.
Note: The MOD 112 transmits audio with excellent fidelity. Therefore, be sure to
connect its input to a signal source that supply the highest quality audio your
system can offer. The signal should not be processed by an equalizer used for an
accompanying PA system.
The MOD 112 has excellent signal processing, so the use of an additional limiter
or compressor is not recommended.
INSTALLATION STEP 5: TESTING THE SYSTEM
Step 1: After the baseband cable, power cables, and audio source are connected, turn the
MOD 112 power switch on. The green power LED on the front of the MOD 112
should light.
Step 2: Make sure the sound system is on and your audio source is active. Adjust the
Audio Level Control. Check the quality of your audio source signal by listening
through the Phones jack on the MOD 112’s front. The MOD 112’s 10-segment bar
graph level indicator shows audio level in 3 dB steps at the input of audio level
processing circuit.
Step 3: Look at the TX8 Emitter panel(s). With the baseband signal and power connected,
two red lights should be visible from directly underneath the panel: the power
indicator on the right and the baseband indicator on the left. The baseband light
will go off if the modulator carrier goes off–as it will after 30 minutes of no audio.
Step 4: Hold a receiver near the “Infrared Test Out” LED on the front of the MOD 112.
Turn the receiver on and adjust the volume. You should be able to hear the audio
signal through the receiver. If not, make sure the “CXR On” Indicator is lit and
there is activity on the Level Indicator. If the lights are not flashing, check your
audio source or the setting of the input level switch and input level control. If the
audio lights are flashing, but you don’t hear anything from the receiver, try a
different receiver to be sure the receiver is working.
Step 5: Take a receiver into the listening area and walk around to check the reception.
Make sure the transmitter and receivers are set to the same frequency. Make sure
the “eye” on the receiver is not covered up when in use. The receiver will not work
if it is placed in a pocket or purse; its eye must be able to “see” the transmitter
panel. Williams Sound’s optional WIRM-1 Infrared Field Strength Meter may be
used to check signal strength if the system is operating on 95 kHz.
It may be necessary to adjust the angle of the transmitter to obtain the best
coverage. If coverage is not adequate, add one or more WIR TX8 Transmitter
panels to the system. (See page 10, If You Are Using More Than One Emitter)

Williams Sound ®
Helping People Hear
14
CONTROLS AND FEATURES
MOD 112 FRONT PANEL
POWER SWITCH
Turns the entire system on and off. The associated wall mounted power supply stays on at all
times and may operate continuously. There is no “wear out” mechanism.
POWER ONINDICATOR
Indicates actual operation of modulator. Does not indicate status of power supply.
LEVEL CONTROL
Controls level of audio signal. The control is connected between the input amplifier and the
audio level processing circuit.
LEVEL INDICATOR
Bar graph level indicator shows audio level in 3 dB steps at input of audio level processing
circuit. Indicator is peak responding and is calibrated so that optimum level is reached when
the amber +3 light usually blinks and the red +6 light only blinks occasionally.
CXR ONINDICATOR
The Carrier On indicator shows when the carrier is on. The carrier comes on when power is
applied, but goes off automatically if there is no audio for approximately 30 minutes. Audio
sufficient to light the –21 level indicator light will reset the timer, allowing another 30
minutes before the carrier can again go off.
After the carrier has automatically gone off, audio sufficient to light the –21 level indicator
light will turn the carrier back on immediately.
Phones
Infrared
Test Out
MOD 112 Two-Channel Infrared System Modulator Williams Sound
Power
CXR
Limit
Compress
Discrete
Stereo
Audio Mode Phones
CH1
CH2
CXR
-21 -18 -15 -12 -9 -6 -3 0 +3 [phone] +3 +6
5
0
1
2
346
78
9
10
CH 1 Level CH 2 Level
Channel 1 Channel 2
5
0
1
2
346
78
9
10
Power On Indicator
Indicates actual
operation of unit.
Power Switch
Turns the entire system on
and off. The associated wall
mounted power supply stays
on at all times.
Level Indicators
Bar graph level indicator
shows audio level ijn 3 dB
steps at input of audio level
processing circuit.
Audio Processor Switch
Selects one of the two
modes: Limit and
Compress
Mode Switch
Separate processing for
each channel is provided
in the Discrete mode,
coupled processing is
provided for Stereo
Mode.
IR LED
Infrared
receivers can
be tested
using the IR
LED.
Phones Jack & Switch
The phones jack monitors the
audio in one, the other or both
channels, depending on the
setting of the Mode and Phones
switches.
CXR On Indicator
The Carrier On indicator
shows when the carrier is on.
Level Controls
Control level of
audio signal.
FIGURE 9: MOD 112 FRONT PANEL

Williams Sound ®
Helping People Hear
15
AUDIO PROCESSOR SWITCH
Selects one of the two modes available.
LIMIT MODE
The audio processor has little effect on low level sound. As the level increases, reaching
the point at which the red +6 LED lights, no further increase in transmitted level is
permitted. This is necessary to prevent distortion in receivers and prevent interference
with other channels. Limit produces a very natural sound, and is most desirable for
music. High quality speech signals are also very pleasant to listen to. However, Limit is
not as helpful for hearing impaired individuals as Compress mode.
COMPRESS MODE
At high levels, 0 to +6, Compress is very similar to Limit. But at low levels Compress
increases the volume substantially. Hearing impaired people need an increase in low
level to be able to hear most speech.
Compress is most useful for hearing impaired individuals and in those situations where
the input signal is either poorly controlled or has great dynamic range.
MODE SWITCH
The Mode Switch selects how the channels are used. Separate processing for each channel is
provided in Discrete mode, where the two channels have unrelated program material such as
two different languages. Coupled processing is provided for Stereo mode, where the
program material is related.
DISCRETE MODE
The channels operate fully independently. Carrier timers operate separately, allowing
one channel to go off without affecting the other. The Phones jack receives one or the
other channel, as selected by the Phones switch. Both channels of the Phones jack have
the same signal.
STEREO MODE
Audio processing is coupled, providing a consistent stereo image, important when
listening with headphones. Carrier timers are coupled, requiring both to have reached
approximately 30 minutes before either carrier can go off. Both carriers go off and on
together. The Phones jack receives stereo sound, one channel in the left side and the
other channel in the right side. The Phones switch is deactivated.
PHONES
The phones jack monitors the transmitted audio signal. It is designed to accommodate
standard professional headphones with a 1/4 inch plug. It can also accept any other type of
headphone or earphone. Headphones with 3.5 mm plugs can be used with a 1/4 inch to
3.5 mm adapter.
IR LED
Infrared receivers can be tested using the infrared LED. This LED is of short range only,
useful to about 1 meter. The infrared signal emitted from this LED is modulated by the
carriers generated in this unit only. If this modulator is connected to other modulators for
additional channels, their carriers are not emitted by the LED, and must be monitored at
those modulators.

Williams Sound ®
Helping People Hear
16
MOD 112 REAR PANEL
AUDIO INPUTS 1 & 2
The MOD 112’s inputs accepts any low impedance microphone or line level signal. The
input circuit is constructed with a “studio grade” differential amplifier, providing better
performance than that available using a transformer. It is also fully protected from RFI/EMI.
MICROPHONE
Any dynamic, ribbon, or condenser microphone equipped with a balanced output and a
3 pin XLR connector can be used. Power is supplied for condenser microphones
according to DIN 45596. It need not be turned off for dynamic or ribbon mics.
Microphones with two conductor 1/4 inch plugs are not usable.
The minimum acceptable level is approximately 100 µV, and the maximum level before
clipping is approximately 90 mV.
LINE
Both balanced and unbalanced line level signals can be accommodated. The minimum
acceptable level is approximately 100 mV, and the maximum level before clipping is
approximately 10 V.
25 V, 70 V, and 100 V speaker distribution lines can be connected to the Line input using
attenuators made with resistors or with speaker-matching transformers. Resistor
attenuators yield better results. The minimum acceptable level is approximately 100 mV,
and the maximum level before clipping is approximately 10 V.
ACCESSORY INPUT
Outputs are available directly from several points in the internal circuitry of the modulator.
(See Figures 10 and 11.)
Model WIR MOD112 Two-Channel Infrared System Modulator
Accessory
Power: 24 VAC,
50-60 Hz, 10VA
Williams Sound Corp., Minneapolis, MN USA
Balanced
Mic (XLR)
Bal or Unbal
Line (1/4")
Ch 1 Audio Input Ch 2 Audio Input
Baseband
Output
Baseband
Input
50 Ohms 50 Ohms
Input 1 & Input 2
These inputs to the modulator
accept any low impedance
microphone or line level signal.
Baseband Output
Carrier tones of 95 kHz and 250 kHz are provided at
this BNC connector. One 50 Ωdevice may be
connected here using RG-58 cable. Additional
devices may also be connected in series.
Accessory Connector
Outputs are available directly
from several points in the internal
circuitry of the modulator.
Baseband Input
An additional modulator may be
connected here to allow combining
carriers for more channels. The input
impedance is 50 Ω.
Power In
21 VAC to 26 VAC only, 50 or 60 Hz.
120 VAC (US): TFP 010
230 VAC (CE): TFP 027
Current consumption is approx. 130 mA.
FIGURE 10: MOD 112 MODULATOR REAR PANEL

Williams Sound ®
Helping People Hear
17
BASEBAND OUTPUT
Carrier tones of 95 kHz and 250 kHz are provided at this BNC connector. One 50 Ωdevice
may be connected here using RG-58 cable. Additional devices may be connected by
“looping through” the connected device or by means of a suitable distribution amplifier.
The output impedance is 50 Ω. Frequency accuracy is approximately ± .005%. Deviation is
±50 kHz, maximum. Average deviation is dependent on program material and whether
Limit mode or Compress mode is selected.
BASEBAND INPUT
An additional modulator may be connected here to allow combining carriers for channels in
addition to 95 kHz and 250 kHz. The input impedance is 50 Ω.
POWER IN
21 VAC to 26 VAC only, 50 or 60 Hz (TFP 016 Power Supply). Current consumption is
approximately 70 mA. (TFP 027 Power Supply for 240 VAC installations)
TX8 EMITTER
POWER INPUT
Three-pin connector for TFP 010 or TFP 027 (for 240 VAC installations) power supply.
POWER INDICATOR LED
Visible through the left side of the bottom panel. Red indicator light glows when power is on.
Note: The TX8 shuts off when no baseband signal is present.
VCO
VCO
STEREO
2 CH
95 KHz
250 KHz
VCO
VCO
DIRECT OUT 1
PROCESSED OUT 1
PROCESSED OUT 2
CIRCUIT COMMON
CINE OUT 1
CHASSIS
CINE OUT 2
DIRECT OUT 2
LOW PASS
FILTER
PREEMPHASIS
LEFT INPUT
+ 15 V
LIMIT
+ 15 V
MIC
MIC 12
3
12
3
T
TS
SS
S
RS
R+
1
6
2
7
3
8
4
9
5
–
+
–
T
TS
SS
S
RS
R
RIGHT INPUT
LINE
LINE
COMPRESS
INPUT 1
50 µSec
LOW PASS
FILTER
PREEMPHASIS
INPUT 2
ACCESSORY
POWER
REGULATED
POWER
SUPPLY
24 VAC
POWER IN
+15 VDC 3
2
1
+15 VDC
–15 VDC
CIRCUIT COMMON
50 µSec
CARRIER
TIMER
LEVEL
DETECTOR
10
LIGHT
BAR
GRAPH
DEV. CAL.
CARRIER
CARRIER
SYNTH
OUT AMPL W/DEEMPH PHONES
BASEBAND
OUTPUT
BASEBAND
AMPLIFIER
BASEBAND
COMBINER
INPUT
SYNTH
CARRIER
TIMER
LEVEL
DETECTOR
10
LIGHT
BAR
GRAPH
DEV. CAL.
FIGURE 11: MOD 112 CIRCUIT DIAGRAM

Williams Sound ®
Helping People Hear
18
BASEBAND INDICATOR LED
Visible through the left side of the bottom panel. Red indicator light glows when power is on.
BASEBAND IN
Connects to the Baseband Out jack of the MOD 112 modulator or another TX8 emitter.
BASEBAND OUT:
Connects to the Baseband In jack of of the next TX8 emitter in the chain when multiple
emitters are used.
WALL/CEILING MOUNT TEMPLATE:
A mounting bracket (BKT 024) is included with the emitter. An optional tripod stand kit is
also available (WSC Part #SS-6, SS-10).
Note: The WIR TX8 Infrared Emitter is a Class 1 LED product.
Power
Connection
Plug in TFP 010
Power Supply
In
Baseband (Modulation)
Out
24
Power On Baseband On
CNC
50 Ohms
Multi-Channel Infrared Transmitter Helping People Hear
Made in U.S.A.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK DO NOT EXPOSE THIS
EQUIPMENT TO RAIN OR MOISTURE.
Power In:
24VAC
50-60Hz
30W
Williams Sound Corp., Minneapolis, Minnesota, USA
Power Supply Wiring:
Use NEC, Class 2 Wiring, 18 ga. minimum,
200 ft. (61 m) maximum length (18 ga.)
Baseband Signal Wiring:
Use RG58 Coax,1000 ft. (305 m) max. length
Note: It is normal for this unit to feel warm while it is in operation.
Plug
Williams Sound®
Mounting
Template
Baseband Out
BNC Connector,
50 Ω, 50 kHz–1 MHz
Baseband
Baseband In
BNC Connector,
50 Ω, 50 kHz–1 MHz
Baseband
Wall/Ceiling
Mount Template
Set of threaded holes
for use with the BKT 024
(Pana-Vise) bracket.
FIGURE 12: TX8 EMITTER REAR PANEL
Power LED
Indicates transmitter is on when lit.
Baseband LED
Indicates presence of baseband signal
FRONT
BACK
FIGURE 13: WIR TX8 BOTTOM PANEL

Williams Sound ®
Helping People Hear
19
RECEIVER INSTRUCTIONS
TWO CHANNEL IR RECEIVER MODEL WIR RX5
Make sure the “eye” on the front of the receiver is not covered up when in use. The receiver
is intended to be worn on the front of the body, hanging from the lanyard attached to the
receiver. The receiver will not work if it is placed in a pocket or purse. A variety of
earphones, headphones, or a neckloop telecoil coupler can be used with the RX5 Receiver.
Step 1: To install the batteries, open the battery compartment using a coin in the slot in the
bottom of the receiver. Press two AA batteries into place, observing proper battery
polarity.
Step 2: Plug the earphone or headphone into the earphone jack.
Step 3: Turn the receiver on by rotating the volume control knob clockwise.
Step 4: Choose the appropriate channel using the push-button channel selector.
Step 5: Adjust the tone to your preference using the slide switch tone control. To avoid
draining the battery, make sure the receiver is turned off when not in use.
STEREO IR RECEIVER MODEL WIR RX6
Make sure the“eye” on the front of the receiver is not covered up when in use. The receiver
is intended to be worn on the front of the body, hanging from the lanyard attached to the
receiver. The receiver will not work if it is placed in a pocket or purse.
A variety of stereo earphones and headphones can be used with the RX6 Receiver.
Step 1: To install the batteries, open the battery compartment using a coin in the slot in the
bottom of the receiver. Press two AA batteries into place, observing proper battery
polarity.
Step 2: Plug the earphone or headphone into the earphone jack.
Step 3: Turn the receiver on by rotating the volume control knob clockwise.
Step 4: Adjust the tone to your preference using the slide switch tone control. To avoid
draining the battery, make sure the receiver is turned off when not in use.
!! IMPORTANT WARNINGS !!
DO NOT ATTEMPT TO RECHARGE ZINC CARBON (“HEAVY DUTY”), ALKALINE, OR
LITHIUM BATTERIES!
DO NOT ATTEMPT TO RECHARGE SINGLE-USE BATTERIES! These batteries may heat up
and explode, causing possible injury and damage to the equipment.
Avoid shorting the plus and minus battery terminals together with metal objects. Battery
damage and burns can result!
Use only Williams Sound supplied chargers and batteries!

Williams Sound ®
Helping People Hear
20
BATTERY INFORMATION
For RX5 and RX6 Receivers in normal use, a AA alkaline battery (BAT 001) will last about
30 hours. Rechargeable AA batteries will last about 15 hours per charge.
If you are using BAT 026 rechargeable batteries, use the CHG 200A Multi-Charger. Contact
your dealer or Williams Sound for details.
If the sound becomes weak or distorted, replace the batteries. The indicator light may still be
on, even with weak batteries. Do not leave dead batteries in the receiver, they may leak and
damage the receiver.
RECEIVER MANAGEMENT
Different types of facilities will use different approaches for receiver management and
earphone sanitation. Below are some options that customers have used successfully.
Regular users purchase their own receiver and take care of their own batteries and
earphone.
Some facilities label the receiver and earphone with the names of regular users so each
person uses the same receiver and earphone.
Ushers issue receivers to people who request them. Earphones are sanitized after use.
Foam ear cushions can be replaced or washed with a mild detergent, rinsed thoroughly
and air-dried. The EAR 022 Surround Earphone can be sanitized with an alcohol pad.
The receivers can be stored in a multiple compartment storage case with a credit card or
driver's license left as collateral for the receiver.
Regular users purchase their own earphone or headphone and bring them to use with
receivers at the facility.
Some facilities use the drop-in style CHG 200 Multi-charger for both storing and
charging receivers.