MR-202/MR-204 TWO- AND FOUR-CHANNEL HEADSET STATIONS USER MANUAL
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.
MR-202/MR-204 Two- and Four-Channel 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™ System Installation Manual.) 4.
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.
MR-202/MR-204 Two- and Four-Channel 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.
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 channels. 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.
MR-202/MR-204 Two- and Four-Channel 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.
Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations Pin 1 2 3 Channel A 1 XLR Connector MR-202 Intercom Connector FIGURE 3: MR-202 Intercom Wiring 2 Pin 1 3 Channel A 3 Channel B 3 Channel C 3 Channel D 1 2 1 2 1 MR-204 Intercom Connector 2 1 XLR Connectors FIGURE 4: MR-204 Intercom Wiring 9—Option Board Jumpers The two jumper plugs, P1 and P3, must be installed when optional modules are not used.
MR-202/MR-204 Two- and Four-Channel Headset Stations EQ/ LIM Sidetone Null Clear-Com Intercom Systems Intercom Volume Headset Mic Headset Output Mic Mute Talk Power Long Line Talk Call Call Send & Receive Microprocessor Latch Disable TW Option Call Light Common +30 VDC Channel Switch RMK Ch. B Ch. A Ground Ch. B 4-Wire Input Ch. A 16 VAC Rectifier Power 2-Wire / 4-Wire Select Ch. B 4-Wire Output 4-Wire Option Ch. A FIGURE 5: MR-202 Block Diagram Rev.
Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations EQ/ LIM Sidetone Null Intercom Volume Headset Mic Headset Output Mic Mute Talk Power Long Line Talk Call Call Light TW Option Call Send & Receive Microprocessor Latch Disable Ch. D Ch. C Common +30 VDC RMK Channel Switch Ch. B Ch. A Ground FIGURE 6: MR-204 Block Diagram Troubleshooting • System does not operate. Talk Light does not come on when Talk button is pressed.
MR-202/MR-204 Two- and Four-Channel 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.
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.
MR-202/MR-204 Two- and Four-Channel Headset Stations Clear-Com Intercom Systems PARTS LISTS Parts List for the MR-202/MR-204 Main PCB and Chassis Capacitors Value .01 4.7 .047 100 22 22 22 47 220 470 .0022 .0047 .01 .047 .1 .22 .47 1 4.
Clear-Com Intercom Systems 15.0K 20.0K 100K 121K 221K 475K 1.
MR-202/MR-204 Two- and Four-Channel Headset Stations Clear-Com Intercom Systems FIGURE 7: Main PCB Component Layout Rev.
FIGURE 8: MR-204 Main PCB © Clear-Com Intercom Systems 2000 15 Rev.
MR-202/MR-204 Two- and Four-Channel Headset Stations Clear-Com Intercom Systems This page is a place holder. Rev.
Clear-Com Intercom Systems MR-202/MR-204 Two- and Four-Channel Headset Stations Technical Specifications Headset Microphone Pre-Amp Input Type: Impedance: Input Level: Gain from headset mic to intercom line: Dynamic 1k ohms -55 dBV nominal; -10 dBV max.
MR-202/MR-204 Two- and Four-Channel 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.
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.
MR-202/MR-204 Two- and Four-Channel 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.
4065 Hollis Street, Emeryville, CA 94608 (510) 496-6666 Fax (510) 496-6601 Manual Part Number 810256 Rev.
