Clear-Com MR-202, MR-204 User Manual

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MR-202/MR-204

TWO- AND FOUR-CHANNEL HEADSET STATIONS

USER MANUAL

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Introduction

Congratulations and thank you for choosing this Clear-Com product. The MR-202 Two-Channel and MR-204 Four-Channel Headset Stations are

powerful, yet user-friendly units that can serve as versatile intercom stations. Please read this manual completely to better understand the functions of

these products. For questions not addressed in this manual, contact the dealer or Clear-Com directly. Clear-Com applications support and service people are ready to help.

Description

The Clear-Com PL-Pro™ MR-202 and MR-204 are headset stations ideal for use in theatres, live performances, industrial environments, and small television facilities. They feature speech intelligibility in all noise levels and can be customized through their programmable options.

Selectable, multi-channel talking and/or listening allows the operator to communicate on one of two (MR-202) or four (MR-204) intercom channels. The dual-action talk button operates in electronic momentary or latching mode. The MR-202 and MR-204 offer visual call signaling to attract the attention of operators. The Remote Mic Kill (RMK) feature on main stations will turn off any open microphones on these headset stations.

The MR-202 and MR-204 stations accept dynamic headsets, such as the Clear-Com PL-Pro

control allows the operator to vary the level of his voice heard in the headset. The MR-202 and MR-204 receive 30-V DC power from the Clear-Com

intercom line. They mount in a standard two-gang electrical outlet box. The extra-thick front panel and compact, surface-mount circuitry results in a small size and lighter weight package that maintains Clear-Com ruggedness. The intercom channels connect to a plug-on screw terminal strip.

™

or the HS-6 T elephone Headset Series. A sidetone

The optional EB-TW daughter board module can be installed to provide an interface to two intercom channels on a single microphone cable. Also, the EB-TW 4-Wire daughter board module is available to allow long-distance connections using separate pairs of wire for send audio and receive audio. The EB-4W 4-Wire option supports two-channel operation and may only be used on the MR-202.

The MR-202 and MR-204 are compatible with all Clear-Com Party-Line intercoms.

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

Quick Start

1. Unpack the unit and inspect for any damage that may have occurred during shipping.

2. Connect the intercom lines. If less than the maximum number of intercom lines are to be connected, link unused intercom inputs to a connected input with jumper wires.

3. Install the MR-202 or MR-204 into the two-gang outlet box. (For additional information, refer to the Clear-Com PL-Pro

Installation Manual.)

4. Connect the appropriate headset or handset.

5. Set Listen Levels and Sidetones. (Refer to “3—Intercom Level Control” on page 4 and “4—Sidetone Control” on page 4.)

6. The headset station should now be operating properly.

7. Read the rest of this manual for further information.

™

System

Operation

Normal operation of the MR-202 or MR-204 Headset Station only requires the front-panel controls. The controls located elsewhere on the unit are intended to be set-and-forget in nature. For intercom operation, set the Listen level control to the desired level and press the Talk button when talking. Set the Sidetone control for the desired amount of sidetone in the earphone.

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Front Panel

The controls, indicators, and connectors found on the MR-204 front panel are shown in Figure 1 on page 3 and are described by the following text. The MR202 front panel is identical except the channel switch has two positions.

3 5

Intercom Level

Call

Sidetone

Talk

A B C D

Channel Select

pro

MR-204

R e m o t e

S t a t i o n

1—Talk Button and Lamp

The Talk button activates the microphone feed to the selected intercom channel. The Talk button has a dual action (momentary or latching) depending upon how the button is pressed. If desired, the latching function can be defeated using an internal switch. The following describes the various functions of this button.

• Momentary—Press and hold the Talk button while speaking. Release it when finished.

• Latching—Press and release the button quickly to latch the Talk function. Press and release the button again to turn off the Talk function.

FIGURE 1: Front Panel

Rev. B

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

• Talk Indication—The associated Talk lamp will illuminate green when the Talk function is activated.

2—Call Button and Lamp

Pressing the Call button will send a call signal on the selected channel. All the call lights on that channel will then flash. Call signals can also be sent while talking if required. The C all lamp will light while the Ca ll button is pressed, or whenever a call signal is present on the selected channel.

3—Intercom Level Control

Turn this control to set the listen level required on the headset.

4—Sidetone Control

Sidetone is the level of the operator’s voice that heard while talking on the intercom. Setting a comfortable level of sidetone will ensure that the intercom line sounds alive and also helps modul ate the oper at or’s voice relative to other voices on the line.

Use the following procedure to correctly set the Sidetone level control.

1. Set the Intercom Level control to a comfortable level by having

someone talk to the operator from another station.

2. Press the Talk button and speak into the microphone while

turning the Sidetone control slowly back and forth until you hear your voice at a comfortable level in the headset.

Note:

Do not force the trimpot past its stop points. This will damage it.

5—Channel Switch

This switch selects the intercom channel (A, B, C, or D) on which the headset station is active.

6—Headset Connector

The headset connector is located on the front panel. All Clear-Com headsets are recommended for use with the MR-202 or MR-204. The Clear-Com PT-4 Push-to-Talk Microphone or the HS-6 Telephone Handset will also plug into the headset connector. The following is a description of the characteristics of a suitable headset:

• Mic Type—Dynamic; 150 to 400 ohms impedance; -55 dB output level

• Headphone—Dynamic; 50 to 2000 ohms impedance.

The wiring of the headset is to be as follows:

• Pin 1—microphone ground (shield)

• Pin 2—microphone hot

• Pin 3—headphone ground

• Pin 4—headphone hot.

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

The microphone and headphone wiring in the headset cord must be individually shielded.

Note:

Do not connect Pins 1 and 3 together. Headset extension cords or headset “Y” cables are not recommended because they may increase crosstalk between channe ls .

Internal Adjustments and Connections

The controls and connectors found inside the MR-202 and MR-204 are shown in the following figure and described by the following text. The jumpers can be accessed without completely removing the panel from its wall box by removing the top two screws and loosening the bottom two screws a few turns. The panel can then be leaned out from the wall. The jumpers will be accessible as shown in the lower view of Figure 2 on page 5.

P3 Must be

installed if

no option

JB2

JB1

P1 Must be

installed if

no option

View from top

of MR-202

Front Panel

FIGURE 2: Internal Adjustments and Connections

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

7—Option Jumpers

Two option jumpers, JB1 and JB2, are provided. They should be configured when the system is set up, but shouldn’t need to be changed during normal operation.

Note:

The default position of the jumpers is in the OPEN (only one pin

connected) position. The function of each jumper is as follows:

JB1—Long Line

If a long cable run is unavoidable and approaches 1,000 ft. or more, set the Long Line option jumper to the CLOSED (both pins connected) position. The ability to set a sidetone null depends upon properly setting this jumper.

JB2—Latch Disable

Setting the Latch Disable jumper to the CLOSED (both pins connected) position will disable the latching function of the Talk button. In this mode, the Talk button must be held in continuously while the operator is talking.

8—Intercom Line Connection

The MR-202 contains a five-terminal, plug-on connector for intercom line connection. The MR-204 contains a seven-terminal, plug-on connector for intercom line connection. This connector is intended to be unplugged from the circuit board when connecting the intercom line(s), and then plugged back on when the wiring is completed. If less than the maximum number of intercom lines are to be connected to the intercom connector, link unused intercom inputs to a connected input with jumper wires. The connections for each pin are visible on the circuit board when the connector is unplugged. The pinout of this connector is as follows:

• Pin 1—(NC)

Rev. B

• Pin 2—Channel A Audio

• Pin 3—Channel B Audio

• Pin 4—Power (+30 VDC)

• Pin 5—Ground (Shield)

• Pin 6—Channel C Audio (MR-204 only)

• Pin 7—Channel D Audio (MR-204 only).

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Pin 1

MR-202 Intercom

Connector

FIGURE 3: MR-202 Intercom Wiring

Pin 1

MR-204 Intercom

Connector

XLR

Connector

1 2

Channel A

Channel B

Channel C

Channel D

9—Option Board Jumpers

The two jumper plugs, P1 and P3, must be installed when optional modules are not used. When the optional 4-Wire or TW Modules are used, both P1 and P3 must be removed. Save these jumper plugs for possible future.

Note:

The MR-202 and MR-204 will not operate without either these jumper

plugs or the optional modules installed.

XLR

Connectors

FIGURE 4: MR-204 Intercom Wiring

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

Headset

Mic

Talk

16 VA C

4-Wire Option

Microprocessor

Latch

Disable

Rectifier

EQ/ LIM

Mic

Mute

Talk

RMK

Power

Sidetone

Null

2-Wire / 4-Wire

Select

Long Line

Call

Call Send &

Receive

Call Light

Channel

Switch

Intercom

Volume

Headset

Output

Power

TW Option

Common +30 VDC

Ch. B

Ch. A

Ground

Ch. B

Ch. A

Ch. B

Ch. A

4-Wire

Input

4-Wire

Output

Rev. B

FIGURE 5: MR-202 Block Diagram

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Headset

Mic

Talk

Microprocessor

Latch

Disable

Troubleshooting

System does not operate. Talk Light does not come on when Talk

•

button is pressed Scenario 1

EQ/ LIM

Mic

Mute

Sidetone

Null

Talk

RMK

Long Line

Call

Call Send &

Receive

Call

Light

Channel

Switch

FIGURE 6: MR-204 Block Diagram

Intercom

Volume

Headset

Output

Power

TW Option

Ch. D

Ch. C Common +30 VDC

Ch. B

Ch. A

Ground

The MR-202 or MR-204 doesn’t have an intercom connection. If the EB-4W 4Wire Option Module is connected, the MR-202 may not be receiving AC power.

Solution: Check connections and cable.

Scenario 2

The MR-202 or MR-204 has an internal failure. Solution: Unit requires servicing.

Headset does not operate. Talk Light comes on when Talk button

•

is pressed

Scenario 1

The headset unplugged, the Intercom Level knob is turned all the way down, or the Channel switch set to unused channel.

Solution: Adjust controls appropriately.

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

Scenario 2

Defective headset. Solution: Test with another headset.

Scenario 3

Plug P3 is missing on circuit board. Solution: Plug P3 must be installed in the J3 jack if the EB-4W or EB-TW

option is not used.

Hum or buzz in system

•

Scenario 1

Inductive pickup caused by close proximity of this headset station or connected stations to power lines or transformers.

Solution: Relocate the offending unit or wiring. If the cable run is exceptionally long, consider adding and using the EB-4W 4-Wire Option Module. (Requires an additional 4-wire interface at the opposite end of the “long run.”)

System feedback (Acoustical)

•

Scenario 1

Listen Level control at this station or another station is set too high. Solution: Adjust.

Scenario 2

Sidetone Null control at this station or another station is not adjusted correctly. Solution: Adjust. Refer to “Front Panel” on page 3.

Scenario 3

Channel not terminated. Solution: Set the Main Station or Power Supply termination switch for that

channel to the ON position.

Scenario 4

The Channel switch is set to an unconnected channel. Solution: If less than the maximum number of intercom lines are to be

connected, link unused intercom inputs to a connected input with jumper wires.

Scenario 5

A headset extension cord was used. Solution: Headset extension cords are not recommended because they

increase crosstalk.

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Excessive crosstalk

•

Scenario 1

High DC resistance in ground return. Solution: Use heavier cable; add additional conductor(s) to ground return. If

the cable run is exceptionally long, consider adding and using the EB-4W 4Wire Option Module.

Scenario 2

Multi-channel cable pairs are not individually shielded. Solution: Replace cable with individually shielded pairs.

Scenario 3

Headset cables are not wired properly or shielded properly. Solution: Correct wiring. Use headsets with properly shielded wiring.

• The Call signal does not function. Scenario 1

Excessive DC loading of intercom line. Solution: Remove any audio transformers or other equipment which may be

connected across the intercom line. If equipment other than Clear-Com intercom equipment must be connected to the intercom line, please contact Clear-Com application or service personnel for advice.

Scenario 2

Far too many terminations on the intercom line. Solution: Check all main stations and power supplies to make sure each

intercom channel is terminated at only one point.

Scenario 3

Plug P1 missing on circuit board. Solution: Plug P1 must be installed in the J1 jack if the EB-4W or EB-TW

options are not used.

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

PARTS LISTS

Parts List fo r the MR-202/MR-204 Main PCB and Chassis

Capacitors

Value Type Volts Tol. Part # Designator

.01 uF Ceramic Disc 1.4KV 20% 150029 C6

4.7 uF Aluminum NP 50V 150087 C10 .047 uF Metal Film 100V 2% 150123 C19 100 uF Aluminum 35V 150136 C27 22 uF Aluminum 35V 20% 150152 C23 22 uF Ta nta lum 16V 150032 C24 22 pF Ceramic Disc SMD 50V 5% 151116 C11 C20 47 pF Ceramic Disc SMD 50V 5% 151120 C2 C16 220 pF Ceramic Disc SMD 50V 5% 151128 C22 470 pF Ceramic Disc SMD 50V 5% 151132 C4 C7 .0022 uF Ceramic Disc SMD 50V 10% 151152 C14 .0047 uF Ceramic Disc SMD 50V 10% 151156 C5 C17 .01 uF Ceramic Disc SMD 50V 10% 151160 C28 C32 C33 .047 uF Ceramic Disc SMD 50V 10% 151168 C15 .1 uF Ceramic Disc SMD 50V 10% 151172 C9 C21 C26 .22 uF Ceramic Disc SMD 50V 10% 151176 C12 C18 .47 uF Tantalum SMD 35V 10% 151184 C31 C34 1 uF Tantalum SMD 16V 10% 151185 C3 C13 C30

4.7 uF Tantalum SMD 16V 10% 151189 C8 10 uF Tantalum SMD 25V 10% 151192 C29

Resistors

Value Power Type Tol. Part # Designator

390 OHM 1/4 Carbon Film 5% 410005 R34

1.3K OHM 1/2 Carbon Film 5% 410075 R9

22.1 OHM 1/10 SMD 1% 411230 R5

39.2 OHM 1/10 SMD 1% 411254 R21 100 OHM 1/10 SMD 1% 411293 R22 R29 221 OHM 1/10 SMD 1% 411326 R11 301 OHM 1/10 SMD 1% 411339 R35 432 OHM 1/10 SMD 1% 411354 R15 825 OHM 1/10 SMD 1% 411381 R31

1.00K OHM 1/10 SMD 1% 411389 R18

1.50K OHM 1/10 SMD 1% 411406 R8

2.00K OHM 1/10 SMD 1% 411418 R17

2.74K OHM 1/10 SMD 1% 411431 R14

6.19K OHM 1/10 SMD 1% 411465 R26

6.81K OHM 1/10 SMD 1% 411469 R13

8.25K OHM 1/10 SMD 1% 411477 R36

10.0K OHM 1/10 SMD 1% 411485 R33

12.1K OHM 1/10 SMD 1% 411493 R16

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

15.0K OHM 1/10 SMD 1% 411502 R12

20.0K OHM 1/10 SMD 1% 411514 R20 R25 R28 100K OHM 1/10 SMD 1% 411581 R23 121K OHM 1/10 SMD 1% 411589 R27 221K OHM 1/10 SMD 1% 411614 R6 475K OHM 1/10 SMD 1% 411646 R24

1.0M OHM 1/10 SMD 5% 411677 R37 10K OHM X4 SMD DIP Isolated1% 416016 R7 47K OHM X4 SMD DIP Isolated1% 416018 R2 R3 100K OHM X4 SMD DIP Isolated1% 416019 R1 470K OHM X4 SMD DIP Isolated1% 416021 R4 Pot 5K TRIMPOT 470063 R19 Pot 5K POT 470081 R30

Diodes and Transistors

Device Description Part # Designator

LED LOW CURRENT GREEN T1 3/4 LED 390021 D6 LED LED, YELLOW, ULTRA BRIGHT T1 3/4 390057 D12 LED LED SMD 0805 RED SMD 391001 D10 D11 IC 7805L POS 5V REGULATOR TO-92 PKG 480088 IC5 Diode BAV70 DUAL DIODE COM CATH... SMD 481019 D4 D13 IC 833 DUAL OPAMP... SMD 481023 IC1 IC2 IC3 Transistor 2222A NPN 40V 600MA... SMD 481026 Q4 Transistor 2907A PNP 60V 600MA... SMD 481027 Q3 Diode BAV99 DUAL DIODE... SMD 481033 D1 D3 D8 D9 Transistor MPSA14 DNPN 30V 300MA... SMD 481038 Q6 Transistor J175 P-CHANNEL JFET... SMD 481056 Q1 Q2 Diode 5.1V 5% ZENER 1/4W... SMD 481061 D5 D7 Transistor MPSA64 DPNP 30V 500MA SMD 481075 Q5 IC MICROPROCESSOR, KB/MR SERIES 710508 IC4

Miscellaneous

Device Description Part # Designator

Connector 5 POS, SCREW TERM. PLUG-IN 5MM 210085 P4 Connector 7 POS, SCREW TERM. PLUG-IN 5MM 210144 P4 XLR 4 PIN M FLUSH MOUNT W/SOLDER CUPS 210286 Switch SB-412 SWITCH KNOB GREY WITH 510030 240024 S1 Pot TRIMPOT SHAFT GREY 240057 R19 Pot KNOB GREY INSERT 240077 R30 Switch ROUND MINIATURE BUTTON BLACK 240081 S3 Switch RECT. MINIATURE BUTTON BLACK 240082 S2 Lens LENS, YELLOW, ROUND FOR T1 3/4 240099 D12 Switch SB-412 SCH#CLA-PV-1X6-MBB-AG-C 510030 S1 Switch DPDT P. B. MINIATURE W/LONG PLUNGER 510107 S3 S2 Wire 4 CONNDUCTOR FLAT CABLE 770017 W1

Rev. B

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

FIGURE 7: Main PCB Component Layout

Rev. B

Page 16

FIGURE 8: MR-204 Main PCB

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MR-202/MR-204 Two- and Four-Channel Headset Stations Clear-Com Intercom Systems

Rev. B

This page is a place holder.

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Technical Specifications

Headset Microphone Pre-Amp

Input Type: Dynamic Impedance: 1k ohms Input Level: -55 dBV nominal; -10 dBV max. Gain from headset mic to intercom line: +41 dB

Pre-Amp Response Curve

Frequency Response: 250 Hz to 12 kHz, contoured for intelligibility Limiter Range: 20 dB

Headphone Amplifier

Load Impedance Range: 50 ohm to 2k ohm Output Level: at least +20 dBV across 600 ohm Distortion: < 0.2% THD at 1 kHz Frequency Response: 200 Hz to 15 kHz, ±3 dB Gain from intercom line: +37 dB Power Output: 110 dB SPL (typical)

Power Requirements

Voltage: 30-VDC standard unit; 16 to 18 VAC with 4-Wire Option Current: 30 mA average

Internal Connectors

Intercom: Five-position, plug-on screw terminals AC Power (4-Wire Option Module): Two-position, plug-on screw terminals

Internal Controls

(2) Option jumpers

Front P anel Connectors

Headset: (1) XLR-4M

Front Panel Controls and Indicators

(1) Intercom volume control; (1) Sidetone control; (1) Talk button; (1) Call button; (1) Channel selector; (1) Talk LED; (1) Call LED

Module

Rev. B

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

Environmental

32 to 122 F (0 to 50 C)

Dimensions

4.625 in. W x 4.5 in. H x 1.75 in. D (117 mm x 114 mm x 44 mm)

Weight

0.52 lbs. (0.23 kg)

Notice About Specifications

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. 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.

Rev. B

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Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations

Clear-Com Limited Warranty

The Clear-Com 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 instructions 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.

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.

For your own records fill in the information below: Model No Serial No. Date Purchased Purchased from (dealer) Address City State ZIP

Factory Service

All equipment returned for repair must be accompanied by documentation stating the return address, telephone number, date of purchase, and a description of the problem.

Note:

Do not return any equipment to the factory without first obtaining a

Return Authorization Number. Send equipment to be repaired to:

Customer Service Department Clear-Com Intercom Systems 4065 Hollis Street Emeryville, CA 94608-3505 Telephone: (510) 496-6666 Fax: (510) 496-6601

Warranty Repairs

If in warranty, no charge will be made for the repairs. Equipment being returned for warranty repair must be sent prepaid and will be returned prepaid.

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MR-202/MR-204 Two- and Four-C hannel Headset Stations Clear-Com Intercom Systems

Non-Warranty Repair

Equipment that is not under warranty must be sent prepaid to Clear-Com. If requested, an estimate of repair costs will be issued prior to service. Once repair is approved and repair of equipment is completed, the equipment will be shipped freight collect from the factory.

Rev. B

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4065 Hollis Street, Emeryville, CA 94608

(510) 496-6666 Fax (510) 496-6601

Manual Part Number 810256 Rev. B

Clear-Com MR-202, MR-204 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual