Clear-Com WBS User manual

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
CLEAR-COM LIMITED WARRANTY
Clear-Com products are warranted to be free from defects in materials and workmanship for a
period of one year from date of sale.
Clear-Com's sole obligation during the warranty period is to provide, without charge, the parts
and labor necessary to remedy covered defects appearing in products returned prepaid to
Clear-Com, 945 Camelia St., Berkeley, Ca 94710-1484, U.S.A.
This warranty does not cover any defect, malfunction or failure caused beyond the control of
Clear-Com, including unreasonable or negligent operation, abuse, accident, failure to follow
instruction in the Manual, defective or improper associated equipment, attempts at modification
and repair not authorized by Clear-Com and shipping damage. Products with their serial
numbers removed or defaced are not covered by this warranty.
To obtain warranty service, follow the procedures described below in "Procedures for Returns"
and "Shipping to Manufacturer for Repair or Adjustment."
This warranty is the sole and exclusive express warranty given with respect to Clear-Com
products. It is the responsibility of the user to determine before purchase that this product is
suitable for the user's intended purpose.
Any and all implied warranties, including the implied warranty of merchantability are limited to
the duration of this express limited warranty. Neither Clear-Com nor the dealer who sells
Clear-Com products is liable for incidental or consequential damages of any kind.
P/N 810065 Rev. B
© 1996 Clear-Com Systems
All Rights Reserved
Clear-Com Systems
929 Camelia St.
Berkeley, Ca 94710
U.S.A.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
While Clear-Com makes every attempt to maintain the accuracy of the information contained in its product
manuals, that information is subject to change without notice
Return Shipping Instructions
Procedures for Returns:
!If repair is necessary, contact the dealer where the unit was purchased.
!If repair through the dealer is not possible, contact the Clear-Com Customer Service
Department, located at the factory, as directed below. They will issue a Return
Authorization Number (RMA).
!Do not return any equipment to the factory without first obtaining a Return
Authorization Number.
!Be prepared to provide your company's name, address, phone number, name of
person to contact regarding the repair, type and quantity of the equipment,
description of the defect and the equipment serial number(s).
Questions regarding returns for repair should be directed to:
Customer Service Department
Clear-Com Intercom Systems
945 Camelia Street
Berkeley, California 94710-1484
Telephone: [phone]
Telefax: [phone]
Shipping to Manufacturer for Repair or Adjustment
All shipments of Clear-Com equipment must be prepaid via United Parcel Service or the best
available shipper. The equipment should be shipped in the original packing container; however, if
the original container is not available, use a suitable container that is rigid and of adequate size. If
a substitute container is used, the equipment should be wrapped in paper and surrounded with at
least four inches of excelsior or similar shock-absorbing material. All shipments should be
directed to the attention of the Customer Service Department and must include the Return
Authorization Number.
Upon completion of repairs, equipment will be returned collect via United Parcel Service or other
specified shipper.
NOTICE ABOUT SPECIFICATIONS
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Performance specifications included in this manual are design-center specifications and are
included for customer guidance and to facilitate system installation. Actual operating performance
may vary.
BEFORE YOU BEGIN . . .
To get the most out of the Wireless Intercom System, read this manual carefully. It will answer
questions you might have about the operation and service of the components in the system.
Clear-Com's Customer Service Department is available to answer questions not covered in this
manual.
A NOTE TO CLEAR-COM USERS
This manual will acquaint you with the operation and care of your Clear-Com wireless intercom
system. To help assure years of satisfaction and reliability, please read it carefully and follow the
recommendations.
Upon receiving your shipment, verify that you have received the number of boxes marked as
shipped on the freight receipt. Also, check immediately for box damage that may have occurred
during shipment. Notify the dealer and the freight carrier if you discover damages or losses, so
claims may be expedited, Carefully unpack the units. We recommend you save the shipping
cartons; they are useful for later reshipping.
Should you ever require service, the Clear-Com factory and your authorized Clear-Com service
center knows your equipment best and has the training and test equipment needed to restore
equipment to peak performance. Please feel free to contact your Clear-Com dealer or the
Clear-Com factory for assistance at any time.
Thank you for selecting Clear-Com products. We assure you of our continuing interest in your
satisfaction
INTRODUCTION
This manual describes the setup, adjustment and operation of Clear-Com's Model WBS-6A
Wireless Intercom Base Station and the model WTR-2 (portable) Wireless Remote Transceiver
(NOTE: The terms portable, beltpack and WTR-2 are used interchangeably). If you have
operational questions not covered in this manual, please consult your dealer or the Clear-Com
factory.
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Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System 5
The WBS-6A Base Station operates from a 115/230 Volt, 50/60Hz AC power mains or from an
external source of 12-18V DC (via the rear panel terminal strip). The WBS-6A supports up to six
WTR-2 wireless beltpacks with or without the interface to a Clear-Com wired intercom system.
The WBS-6A provides one Receive antenna connection and one Transmit antenna connection.
Whip antennas are supplied, but for optimum performance we recommend use of dipole antennas
(Clear-Com Model WDA-1).
Clear-Com offers a variety of headsets for use with the WBS-6A system (Consult your Clear-Com
dealer or the Clear-Com factory for more information). Both the WBS-6A Base Station and the
portable WTR-2 remotes are compatible with standard Clear-Com headsets (See: Setup and
Operation section for details on headset compatibility).
The wireless remote WTR-2 is a portable transceiver designed for use with the WBS-6A Base
Station. In the standard configuration it provides full-duplex, hands-free communication between
a roving user and the base station. The base station's circuitry extends the communication link to
other wireless users sharing the WBS-6A, as well as, to wired intercom users via the intercom
interface. Other modes of portable transceiver operation are: push-to-mute (transmitter remains
on, incoming audio is continuous until interrupted by pressing mute switch) and
push-to-transmit or push-to-talk (transmitter and incoming audio are both off, except when
talk switch is pressed).
The WTR-2 requires two 9-volt batteries. Quality alkaline batteries (such as the Duracell MN1604
or Eveready Energizer No. 522) provide eight to ten hours of continuous operation, with the
transmitter on continuously. You may also use rechargeable 9-volt batteries, provided they are
true 9-volt designs, such as the Varta (NOTE: most 9-volt ni-cad batteries are really 7.2-volt
designs and provide very short service life). Even with quality, true 9-volt rechargeable batteries,
operating life is much shorter than with alkaline batteries, usually 3 to 4 hours and recharging a
9-volt ni-cad battery requires up to 15 hours. An industrial grade rechargeable power pack is also
available. This requires a small modification to the WTR-2 beltpack and a special charger (for
more information contact your dealer).
BASE STATION CONFIGURATION
The WBS-6A consists of up to six receiver modules (one per beltpack), one transmitter module
(one per system), the receiver muticoupler, the power supply subassembly and the main audio
board. This audio board contains the receiver and transmitter interface circuits, control switching
and logic, link circuits and the interface to a wired intercom system.
Though the WBS-6A Base Station can be equipped with modules to support up to six wireless
beltpacks, your system may be equipped for less. You can check for this by examining the serial
number/frequency-assignment label on the back of the unit.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
The Base Station uses up to six different receive frequencies, one for each WTR-2 supported. It
provides a common transmit frequency for all WTR-2's in the system. Audio signals from the six
receivers, the front panel headset, the link input (if active) and incoming intercom voice are
summed and applied to the transmitter. As a result, the beltpack users can hear all system voice
signals (including their own). In a similar manner, all audio sources except incoming intercom
drive the intercom output, and all sources except link in drive the link output. This type of
arrangement essentially configures the WBS-6A and portables as a party-line system, similar to
wired intercom systems.
WBS-6A CONTROLS AND INDICATORS
The WBS-6A Base Station provides several controls and connectors. All switches and level adjust
pots used during operation are located on the unit's front panel. Some auxiliary switches are on
the base station's rear panel. Internal adjustments are pre-set at the factory for optimal
performance.
Front Panel control and connector functions (see Figure 1) are:
I HEADSET CONNECTOR: Accepts the system monitor/operator headset.
II VOL: Local headset-volume control.
III MON SELECT SWITCH: 9-position rotary, enabled when (LOCAL) HEADSET
push-button is out.
IV MODE PUSH-BUTTONS: ENABLE switches for beltpacks 1 through 6 and for
the wired Clear-Com intercom system.
V ACTIVE LEDS (R1-R6): Indicates an RF signal is being received by base station.
VI ACTIVE I/C LED: Indicates wired Clear-Com intercom is active.
VII TRANSMIT LED: Indicates base station transmitter is active.
VIIIRECEIVE LEVEL: Six audio receive level potentiometers for beltpacks 1 through
6.
IX POWER ON/OFF SWITCH: Activates unit.
X LOCAL HEADSET ON/OFF SWITCH: Activates headset and mic.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System 7
Figure 1
THE RECEIVE LEVEL (H) Controls allow convenient level trimming of the audio from each
portable. Typically, you will use them to balance audio levels when a person with a soft voice uses
one of the beltpacks.
THE ENABLE CONTROLS (D) Lets the operator enable/disable the audio from one or more
WTR-2 and the wired Clear-Com line. Typical use is to disable the internal base station receive
modules if the number of beltpacks is less than the number of receive modules or if a portable
goes out of range.
THE ACTIVE LEDS (E) Indicate that an RF signal is being received from the associated
beltpack. These LEDs illuminate, regardless of whether or not the channel has been enabled with
the associated enable switch.
THE LOCAL HEADSET SWITCH (K) When in, activates the local headset mic and lets the
headset function as an operating position. When out, the headset mic is disabled and the earpiece
is connected to the MON SEL switch (C). This rotary switch allows monitoring of:
!The entire system --ALL, or
!Each individual portable receiver separately --R-1 through R-6 or
!The wired intercom only --I/C, or
!The link only --LINK.
Receivers may be monitored whether or not they are enabled with their associated enable switch
(D). This LOCAL HEADSET switch is useful for system trouble-shooting, particularly while
the system is up and running without unnecessary disruption of communications.
REAR PANEL CONTROL AND CONNECTOR FUNCTIONS ARE:
I TX ANT: BNC connector for transmit antenna.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
II SCREW TERMINAL: Screw-type terminal strip for connecting 12 to 18 volts DC
(current drain on a fully configured WBS-6A is approximately 600mA).
III IEC TYPE 320 - AC: Power cord receptacle.
IV INTERCOM CONNECTORS: One male 3-pin XLR and one female 3-pin XLR
(connected in parallel).
V TRANSMIT 3-POSITION SLIDE SWITCH: Center position disables transmitter;
continuous transmit in ON position; transmit when any receiver is active in PTT
position
VI LINK ON/OFF SWITCH: Enables/disables link input/output.
VII LINK CONNECTORS: Male and female 3-pin XLRs for link interconnect.
VIIIRX ANT: BNC connector for receiver antenna.
The link circuits can be used for connection to other audio gear, such as, console inputs and
outputs, external amplified mics, monitor speaker/amplifiers, off-air monitor receivers, etc.. The
interface level is nominal 0 dBm with the input gain internally adjustable over a 20 dB range
(approximate).
WTR-2 WIRELESS BELTPACK
The WTR-2 Beltpack is easy to use and includes just two operating controls: A headset volume
control that also incorporates the on/off switch and a 3-position (latching/off/momentary) audio
control switch.
To adjust the mic gain, access the gain control near the top edge (control panel) of the transmitter
board, through the small hole in the side of the WTR-2 chassis. Accurate adjustment usually
requires use of a deviation meter or service monitor. However, minor adjustments can be made
by comparing audio levels from two different portables via the base station monitor circuits.
Always be sure that the gain is set while using the same type of headset that will be used with the
transceiver.
NOTE: The WTR-2 Beltpack has an audio compressor similar to those used in wired intercom
remote units. Thus, it is possible to set the gain too high, resulting in an increase in background
noise when the user is silent and in "pumping" of the compressor when the user is talking. Do
not set the mic gain higher than necessary to achieve adequate volume at the base station.
If you use a deviation meter, adjust the mic gain control for 3.5 to 4 kHz deviation at normal user
speech levels.
There are no user-adjustable controls on the WTR-2 receiver PCB; missadjustment could lead to
an expensive, time-consuming return to an authorized service location or to the factory.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System 9
The WTR-2 includes a small power on LED indicator near the volume control. Unless the user
has selected the PTT mode, the illuminated LED shows that the transmitter is operating.
SETUP AND OPERATION OF WTR-2 BELTPACK
Setup and operation of the system is quite simple. For the beltpacks, simply install two 9-volt
batteries, plug in the headset and turn on the unit. The portable transceiver has only two
operating controls, a combined on/off/headset volume control and an audio control switch
(3-position rocker: locking, off and momentary).
INSTALLING BATTERIES
Install the batteries in bottom of the WTR-2. We recommend heavy-duty alkaline batteries such
as Duracell MN1604 or Eveready Energizer No. 522. Unscrew the captive screw on the cover to
access the battery compartment.
Install the two batteries with the positive (+) smaller terminal towards the center of the WTR-2
and oriented towards the shiny metal battery contacts. Be sure the battery removal straps are
positioned correctly alongside the batteries to facilitate easy removal.
Replace the battery cover. Be sure the removal tabs are folded over the top of the batteries, out of
the way of the cover.
NOTE: The battery compartment is keyed to resist incorrect installation of the batteries. Unless
excessive force is used, it is not possible to install batteries incorrectly. If the batteries do not fit
easily, DO NOT FORCE THEM. Check the orientation of the battery terminals and correct
any misalignment, then try again.
SETTING TALK/LISTEN CONFIGURATION
The function of the audio control rocker switch is internally programmable to any of three modes.
It is factory-preset for PUSH-TO-ENABLE mode (transmitter remains on; audio is off until
the switch is pressed). The other modes are:
PUSH-TO-MUTE (transmitter remains on; audio is continuous until interrupted by pressing
the switch). This mode lets the user cancel transmitted audio during a cough or during a local
conversation, while continuing to transmit an unmodulated signal (to override weaker interfering
signals that might be received at the master station;
PUSH-TO-TALK or PTT (transmitter and audio are both off until the switch is pressed). This
mode allows simplex communications between an unlimited number of beltpacks without a base
station (a.k.a. PUSH-TO-TRANSMIT). It can also be used when more than one beltpack is
required on an assigned frequency of the WBS-6A.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
The use of the push-to-talk mode is not recommended for normal applications due to the high
sensitivity of the system receivers (which often results in very noisy system output). Typical
sources of interfering signals include spurious outputs from poorly adjusted two-way radio
transmitters; harmonic output from FM radio transmitters; radiated harmonic energy from clock
signals in computers and digital equipment; leakage from CATV/MATV systems; and
inadequately shielded RF test equipment.
PROGRAMMING
Programming for different modes is done via push-on jumpers located on the WTR-2 transmitter
PC board. To re-program:
I Remove the WTR-2 from the case. Detach the battery cover and remove the two
9-volt batteries (if installed). Remove the four small Phillips-head screws on the
bottom of the unit and carefully slide the internal chassis out of the case.
II Locate the push-on jumpers on the transmitter PC board (this PC board is the one
which has the connections to the headset connector and the audio control switch).
The jumpers are located just behind the switch connector (P2), near the battery
terminals.
III Set the CONT/PTT jumper as required (normally to the "CONT"-inuous position).
In the CONT position, the transmitter is on at all times when the WTR-2 is powered;
in the PTT position the transmitter is on only when the audio control switch is
pressed.
IV Likewise, set the PT/PM jumper to the appropriate position. In the PT position,
the audio is enabled whenever the audio control switch is pressed. In the PM
position, the audio is muted whenever the switch is pressed.
NOTES: The push-to-mute (PM) and push-to-talk (PTT) modes cannot be used together, since
no audio would ever be transmitted.
The push-to-mute and the push-to-talk modes do not lend themselves to locking switch operation
as provided by the 3-position rocker switch. An optional momentary-only push-button switch is
available as a replacement for the rocker in these special applications. Contact the factory for
details.
SETUP AND OPERATION OF WBS-6A BASE STATION
The base station is equipped with removable rack-mount ears, so it can be set up as a desktop unit
or in a rack. If you choose rack-mounting, install the accessory ears onto the chassis.
For rack-mount installations, external antennas (WDA-1) are recommended. For desktop use, the
supplied whip antennas are satisfactory, though the level of performance will be lower. For best
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System 11
range and performance, we recommend using separate dipole antennas (Clear-Com model
WDA-1) for the base station's transmit and receive sections. Orient the antennas vertically and set
them up as far apart as possible in an uncluttered place. Use Velcro or tie wraps to mount the
antennas and avoid mounting them with or near anything metal.
After the system is up and running, you can fine-tune the antenna placement. If you need to
extend the antennas farther than the cable permits, contact your Clear-Con dealer for
recommended cable extensions.
After you mount the base station and connect the antennas, plug in the AC power cord and the
Clear-Com intercom cable(s).
If you do not plan to use the link, disable the circuits with the link on/off switch. If the link is to
be used, connect the base station to the external audio equipment (console, etc.) or to a second
(slave) base station with standard, 2-conductor shielded mic cable.
Select the transmitter mode with the rear panel TRANSMIT switch. The ON (continuous)
mode is used normally but use the PTT mode if the base station will be left powered when the
system is not in use. This mode automatically shuts down the WBS-6A transmitter when no
beltpacks are transmitting back to it.
Power up the base station and all beltpacks. Enable the active beltpacks via the ENABLE
pushbuttons on the WBS-6A front panel; disable unused channels to avoid possible interference.
Also, enable the wired intercom if one is connected. At this point the front panel LEDs for all
selected beltpacks, the power LED, TX LED and I/C LED should all be illuminated.
Plug a headset into the base station front panel and select the LOCAL HEADSET mode (push
button in). This allows 2-way communications with the beltpacks and the wired intercom during
setup.
If necessary, adjust the audio levels from each beltpack with the RECEIVE LEVEL controls on
the WBS-6A, while each user talks. Normal position for those controls is mid position (12
o'clock). Each control allows 12dB gain adjustment; bring audio levels up or down (+ or -6dB) as
necessary.
If necessary (to locate a noise problem), select the MON function (LOCAL HEADSET switch
out) to individually monitor the I/C, link and wireless beltpacks. Also, use this mode to turn off
the headset mic during system operation to prevent pickup of extraneous noise.
The wireless intercom system should now be fully operational.
HEADSET COMPATIBILITY
In the normal factory configuration, the WTR-2 and WBS-6A are compatible with standard
Clear-Com headsets that have 4-pin XLR connectors. These headsets feature 200-ohm receivers
and low-impedance dynamic microphones.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
You can use headsets with higher impedance receivers, but the result will be lower headset
volume. Using headsets with less than 50-ohm impedance is not recommended for the WTR-2
beltpack. Impedance, as low as 8 Ohms are acceptable for the base station.
For this configuration, WTR-2 pin assignments are:
!Pin 1: Mic common (ground)
!Pin 2: Mic input
!Pin 3: Headset receiver (high)
!Pin 4: Headset receiver (low)
NOTE: The receiver output in this mode is balanced, neither side is grounded. Therefore, pins 3
and 4 may not be common with pin 1 (mic ground) or with the connector shell. If this is done,
low level and distorted audio will result.
The WBS-6A Base Station's pin connections differ, but the same headset wiring may be used.
The connections are:
!Pin 1: Mic common (ground)
!Pin 2: Mic input
!Pin 3: headset receiver ground
!Pin 4: Headset receiver
Additionally, the WTR-2 and WBS-6A are compatible with headsets equipped with most types of
electret mics. They can accommodate units with 2 or 3-wire interfaces (bias voltage supplied on
the signal lead or with a separate bias connection). In this configuration, the receiver audio is
single-ended and considerably lower in level than in the balanced configuration described above.
Use only headsets with high efficiency receivers, if high ear piece volume levels are required.
To convert the WTR-2 from the standard configuration to the electret configuration, move the
small flat strip connector over one position; this strip connector (on the small cable assembly
running between the 4-pin XLR panel connector and the PCB) has one less pin than the mating
connector on the PCB. In the standard configuration, pin 1 or P1 on the PCB is not connected.
When you move the strip connector over one position so that pin 1 is used, you reconfigure the
headset connector for electret mic headsets. Pin assignments for this configuration for the
WTR-2 and the WBS-6A are:
!Pin 1: Mic bias
!Pin 2: Mic input
!Pin 3: Headset receiver
!Pin 4: Common ground
When using an electret mic, it is necessary to change a configuration jumper on the receiver PCB.
This jumper is located on the bottom of the PCB, near the battery compartment. Move the
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System 13
jumper from its present location, the two pins nearest the bottom of the PCB, to the two pins
nearest the middle of the PCB (In other words, in the dynamic mic configuration, the middle and
bottom pins are jumpered together; in the electret mic configuration, the middle and upper pins
are jumpered). Three-wire electret mics are wired directly to the pins shown. Two-wire mics
require connection of a resistor (approximately 1000-ohms) from pin 1 to pin 2 inside the XLR
connector.
Electret mics normally provide much higher output levels than low-impedance dynamic mics. To
accommodate this difference, the system includes circuitry to adjust the gain downwards by
approximately 20 dB in the electret mode.
The WBS-6A Base Station accomplishes selection of the microphone type via a small switch on
the main audio PCB near the front-panel mic connector. This switch is labeled DYN and
ELECT to indicate the correct position for each mode.
TROUBLE SHOOTING
If you experience difficulty with your Clear-Com wireless intercom system within the first year of
operation, it will be repaired under warranty (see below). Service for older units also may be
obtained from Clear-Com. Contact the factory or your sales representative for more information
The majority of difficulties with Clear-Com wireless intercoms are not due to equipment failure.
This equipment is fully tested before leaving the factory and is inherently reliable. In most
instances, problems arise from incorrect equipment application.
Following are the most commonly encountered application problems. If you have any difficulties
with Clear-Com equipment, please review this information and take any necessary corrective
action before returning the equipment for repair.
BATTERY
The most common problems with wireless intercoms are related to the transceiver batteries.
Clear-Com recommends using only new fresh Duracell MN1604 or Eveready Energizer No. 522
alkaline batteries. No other batteries tested by Clear-Com have provided equal life and reliability.
Unfortunately, batteries purchased in drug stores and supermarkets may not be fresh and often do
not yield rated life (6 to 8 hours is the usual range). Regular 9-volt carbon cells have much shorter
lifetimes (2 to 3 hours for a fresh cell, perhaps less than one hour for a cell that's been sitting on a
shelf for a year). Cheap bargain cells may not work at all, because often they are really 7 volts
instead of 9 volts and can not supply the required current.
Often, rechargeable cells (ni-cads) are used in wireless intercom transceivers. The units
commonly sold are almost always 7.2 volts, not 9-volts and provide only a few minutes of
operation. The only acceptable rechargeable battery we know of is the Varta, a true 9-volt design.
Even the Varta's useable life is much shorter than a Duracell's (usually 3 to 4 hours).
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Battery contacts in the beltpacks must be clean and unbroken. Attempted, forced reverse
insertion of a battery is practically impossible, but the attempt will likely damage the battery
contacts.
Exhausted batteries cause numerous problems, such as distortion, audible squeals, howls, poor
range and off-frequency operation. We strongly recommend that you check the battery prior to
each use and replace it if there is any question about its condition. It is also good practice to
replace the battery with a fresh one in the event of any sort of system problem, because a low
battery can affect operation in subtle ways.
INTERFERENCE
Clear-Com wireless intercom systems are designed specifically to reject interference. However,
interfering signals may fall directly on the receiver frequency, making it impossible to completely
avoid problems. As previously mentioned, such problems can arise if the receiver audio is left
open (receiver enabled) when the transmitter is turned off.
Problems with RF noise sources (fluorescent lights, car ignitions, industrial equipment, etc.) are
rare. Nevertheless, defective fluorescent lighting fixtures generate astonishing amounts of RF
energy. Repairing the fixture usually cures the problem, because normally functioning fixtures
almost never cause trouble. This is true for most other interference sources. So, unless the
equipment is electrically defective, the interference will not adversely affect Clear-Com wireless
equipment. When such a situation exists, the source is a wideband transmitter and nothing can be
done to the wireless equipment to correct the problem without seriously degrading performance.
Fortunately, this type of problem is very rare.
A more serious problem arises from improper selection of wireless intercom operating
frequencies, which are inherently subject to interference due to intermodulation. Fortunately, a
proper initial selection or changing frequencies, almost always corrects such a problem.
Clear-Com offers a free computerized frequency selection service to purchasers of its equipment.
If you know the frequency of other wireless equipment used in a given area, you can choose
interference-free frequencies. However, if equipment is added later without frequency
coordination, an interference problem could arise. Should this occur, contact the Clear-Com
factory or your sales representative for assistance.
GENERAL
Before returning equipment for repair, contact the Clear-Com factory or your sales representative.
Often the problem can be resolved by telephone, avoiding downtime and unnecessary returns.
However, should repair be necessary, Clear-Com will promptly correct the problem and return the
unit.
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System 15
SPECIFICATIONS
WIRELESS SYSTEM
Operating Frequency: 150-216 MHz
Frequency Stability: +/-0.005%, -20 to +60 degrees C
Transmission Modulation Type: Direct FM
Auto Frequency Response: 200 to 7.5K Hz @ -3dB
Range: to 1,500 feet or more (line of sight)
Distortion: <2%
WTR-2 BELT-PACK
TRANSMITTER
Power Output: 45 - 50 mW into 50 Ohms
Harmonics: less than -60 dBc
Spurs: less than -50 dBc
Freq. Deviation: +/-6kHz, peak
RECEIVER
Sensitivity: >0.75 uV for 30 dB S/N
Ultimate S/N: 80 dB minimum (20 kHz flat)
Image Rejection: 75 dB minimum
Output Level: 0 - 3 Vrms into 50 Ohms (175 mw)
Power Required: 6.5 - 9.5 VDC from 9v battery (2)
Current Drain: approx. 70 mA
Battery Life: 8 - 10 hours
Controls: Power On/Off/Volume control; microphone
on/off switch
Indicator: LED power "ON"
Dimensions: 3.8"W x 5.2"H x 1.5"D (9.7cm x 13.2cm x 3.8cm)
Weight: 1.1 lbs (0.5kg)
Construction: High-impact ABS control panel; one-piece
anodized aircraft alloy case
WBS-6A BASE STATION
WBT-T TRANSMITTER MODULE
Power Output: 45 - 50 mW into 50 Ohms
Harmonics: less than -60 dBc
Spurs: less than -60 dBc
Freq. Deviation: +/-6 kHz, peak
WBS-R RECEIVER MODULE
Sensitivity: >0.75 uV for 30 dB S/N
Image Rejection: 80 dB minimum
Ultimate S/N: 80 dB minimum
Intercom Output: meets standard Clear-Com specifications
Power Supply: 115/230 VAC, 50/60 Hz or external
12 to 18 VDC
Current Drain: AC - 20W maximum
DC - 1.0A maximum, 600mA typical
Dimensions: 16.75"W (19" w/ears) x 3.5"H x 10"D
(42.5cm {48.26/ears} x 8.89cm x 25.4cm)
Weight: 11.5 lbs max (5.22kg)
Construction: aircraft alloy aluminum
© Clear-Com 1996 Rev. B

Operating Instructions: CLEAR-COM WBS/WTR Wireless Intercom System
© Clear-Com 1996 Rev. B