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MR-202/MR-204 Two- and Four-Channel Headset Stations

Clear-Com Intercom Systems

Rev. B

4

© Clear-Com Intercom Systems 2000

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 Call lamp will light while the Call 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 modulate the operator’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.

Summary of Contents for MR-202

Page 1: ...MR 202 MR 204 TWO AND FOUR CHANNEL HEADSET STATIONS USER MANUAL...

Page 2: ...ectronic 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 micr...

Page 3: ...Com PL Pro System 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...

Page 4: ...vates 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 defe...

Page 5: ...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 but...

Page 6: ...ctions 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...

Page 7: ...l 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 termina...

Page 8: ...alled 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...

Page 9: ...ck Diagram EQ LIM Headset Mic Sidetone Null Call Light Intercom Volume TW Option Channel Switch Ch A Power Ch B Call Send Receive Headset Output Mic Mute Common 30 VDC Ground Long Line 4 Wire Input 4...

Page 10: ...r 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...

Page 11: ...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 Adju...

Page 12: ...roperly 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...

Page 13: ...60 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 Tanta...

Page 14: ...M 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 D...

Page 15: ...MR 202 MR 204 Two and Four Channel Headset Stations Clear Com Intercom Systems Rev B 14 Clear Com Intercom Systems 2000 FIGURE 7 Main PCB Component Layout...

Page 16: ...Clear Com Intercom Systems 2000 15 Rev B FIGURE 8 MR 204 Main PCB...

Page 17: ...MR 202 MR 204 Two and Four Channel Headset Stations Clear Com Intercom Systems Rev B 16 Clear Com Intercom Systems 2000 This page is a place holder...

Page 18: ...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 Requirement...

Page 19: ...pecifications 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 specific...

Page 20: ...d 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...

Page 21: ...om Systems 2000 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 appro...

Page 22: ...4065 Hollis Street Emeryville CA 94608 510 496 6666 Fax 510 496 6601 Manual Part Number 810256 Rev B...

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