MS-400A Four-Channel Main Station INSTRUCTION and SERVICE MANUAL * I 1Clear-Com II Intercom Systems 945 Camelia St. Berkeley, California 94710 510-527-6666 * Clear-Com 810021 8/15/88 REV.
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MS-400A Installation & Operation Manual 1. INTRODUCTION A. Clear-Com Concept ............. 1 B. MS-400A Description ........... 2 11. INSTALLATION A. Maximum Number of Stations ....3 B. Interconnect Cable............4 C. System Architecture ........... 7 D. System Wiring ................. 8 E. Mounting the Station ......... 14 F. Station Connection ........... 14 G. Set-Up ....................... 14 H. Headsets & Mics .............. 16 i. System Check ................. 16 IlI. OPERATION A.
1. INTRODUCTION 1. A. The Clear-Com Concept Clear-Com is a closed-circuit intercom system that consistently provides highclarity, two-way communications in highA noise and low-noise environments. basic system consists of a single- or multi-channel power supply or main station connected to various single- or multi-channel remote stations. Clear-Com manufactures a wide variety of portable and fixed-installation both All are compatible with each units.
1. B. MS-400A Description? The MS-400A is designed for applications in which a person needs to communicate with up to four other people or groups or either individually people, of simultaneously, while still maintaining between each of the four isolation channels. Controls which affect the input and output at the station (mic, headsets, speaker, and program) are located in a row along the upper right of the front Controls that are recessed bepanel.
11. INSTALLATION Il-A. Maximum Number of Stations Consult the graph below. Match the number of speaker stations in your system If to the number of headset stations. point reached falls within the the shaded section of the graph, one MS-400A will operate the entire system with no reduction in performance.
Il-B. Cable Considerations The MS-400A contains 12 XLR-type, 3-pin connectors: two male and one female per Female connectors facilitate channel. system wiring when more than one power supply, or main station, is connected to any of the channels. Cable runs from the rear panel to connect with all remote stations. Allow three inches behind the unit for cables to extend from the rear panel; avoid sharp bends in cabling.
0 you don't use Belden If cable, use a and similar type, with wire gauges capacitance as specified in this manual. The conductors in the cable, especially In longer runs (over 500 feet) must have low DC resistance (less than 15 ohms per 1000 feet; large diameter conductors) and low capacitance (less than or equal to 55 pF per foot of cable--capacitance between conductor and shield).
Belden Shielded Cables , el SA 0,_ (^ 4< Insulat11on Thickness 401 ofobl ' AWGS (Inch) (Strndlng) Cam. 8413 2 8412 2 lo, NMa O.D1 (Ineh). J Thickness -(Inh). 24 (45x40) .019 .025 .190 20 (26x34) .020 043 268 - Shited COvarag 100 iot>'Nom CsP.' (td/f Sun9sted Wotdng; .Voto*' 30 55 600 30 55 49 _ 84 8762 2 20 (7x28) 014 .028 .196 100 350 27 8760 2 18 (16x30) .018 .028 .222 100 450 24 44 27 49 35 62 8725 8 20 (7.28) .015 .030 .
Il-C. System Architecture The number of ways in which you can set up a four-channel intercom system are nearly infinite. However, the "system architecture" will usually fall into one of two categories: * TYPE 1, in which an MS-400A is the only four-channel station, and it connects to a number of one- and two-channel remote stations as shown in the diagram below.
II-D. System Wiring results in a loss of sidetone null at remote stations, some level loss from remote stations to the main station, reduced headset/speaker output before clipping, and, in the ground conductor, a serious increase in crosstalk. Both physical and electrical considerations are involved in determining the The best system wiring configuration.
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Signalling Configurations in Multi-Channel Systems station In normal circumstances, the CALL light on a two-channel remote selechas station lights only when someone signals on the channel that on travels ted for communication. This is because the Visual Signal voltage. the audio line in the form of DC so that A simple modification may be made to the the system wiring a call to respond will channel one to switched are which stations be applied in both signal on the other channel.
Interfacing with Other Systems Clear-Com's Model AC-IOK Universal Interface, Model AC-10H Telephone Interface, Model 1F4-4 TV Camera Interface, and Model TW-12 Two-Wire System Interface allow you to link Clear-Com with virtually any type of communications system. When your existing system is upgraded with Clear-Com equipment, you may continue to use portions of the older system.
"Typical" Four-Channel Intercom Systems a The diagram on the next page shows a standard Clear-Com system for differ, "typical" application. Since your requirements are likely to vary.
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II-E. Mounting The MS-400A The MS-400A is designed to mount in a standard 19" rack, using 3.5" verticalIt can also mount in a console or ly. The sit atop a shelf if necessary. station extends 9" back from the front panel, but avoid sharp bends in cabling and allow an additional 3" behind the If mounting the station in a unit. console, the cut-out must be very accu- rate, as the front panel extends only a very small amount beyond the top and See page 15 for bottom of the chassis.
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Il-H. Headsets S fMics All headset connectors in Clear-Com gear are the 4-pin, male XLR type. To assure proper level and performance, your headset (or handset or mic) should have the following characteristics-Microphone type: dynamic Impedance: 150-250 ohms Output Level: -55dBv Ear Element type: dynamic Output Impedance: 300-2000 ohms An electret element gooseneck microphone, permanently mounted on the MS400A, is available as a factory-inWhen the gooseneck is stalled option.
. HEADSET EXTENSION CORD IS A4F OR LESS AMM /,c-iX SHIELDED PAIR CAUTION: DO NOT CONNECT PIN 1: MIC GROUND MIC GROUND & HEADPHONE GROUND TOGETHER. PIN 2: MIC HOT PIN 3: HEADPHONE GROUND Pin 4: HEADPHONE HOT S. HEADSET "r CABLE CONNECTIONS A4M *4F 0 A4F2 0~ ~ ~~~~~~~~~~~~~~SHIELDED / a/ ~ leads do not have Headset 8ELDEN Note: 3 (a be shielded on Belden 8734.
O * OPERATION Il. Ill-A. Quick Operation Guide 1. Determine which intercom lines are to be assigned to each Plug connecting cable into the appropriate XLR conchannel. If program monitoring is also nectors on the rear panel. desired, connect the program source to the PROGRAM input on the rear panel and set the gain switch to match the source Connect a paging amp to the STAGE ANNOUNCE output, if level. used. 2.
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III-B. MS-400A Operation The controls on the surface of the front panel are used during normal operation of the station; the controls that are recessed behind the front panel cover plate are normally needed only during station set-up. * In the following explanation of controls, the boldface numbers in parentheses refer to the diagram of the MS400A on page 20.
the operator is monitoring. Each channel's SIDETONE NULL adjustment (this is located behind the unmarked beside each Talk toggle 15, hole, switch) is set at the factory for best null with less than 500 feet of (full) connected cable. Because of the controlled amount of added sidetone, the monitored of channels being number doesn't have much effect on the overall sidetone level.
III-C. Special Features: ISO, IFB, and Split-Feed Headset Operation only while the designated channel's Talk toggle is switched to the momentary (ON) The PIC-4 mutes the program position. to the signalling response audio in voltage that the IFB circuitry sends on Converting a channel the IFB channel.
IV. TECHNICAL INFORMATION IV-A. Circuit Description There are two inputs to the main mic preamp, one for each headset connector. The input from the upper connector is switched, and is also used for the optional gooseneck mic. The two inputs are routed to the summing input of the mic preamp (IC2 pin 2) via J3 pins 5 & 6. A compressor circuit (Ql) reduces the gain (nominally +51 dB with a -55 dBv input) as necessary to maintain an output level The talk signal branches to near 0 dB.
IV-B. Maintance & Warranty Clear-Com's solid-state intercoms, power supplies, and interfaces are designed with a modular "building block" approach for- easy system expansion and field servicing. Our chassis design incorporates highly efficient ventilation and circuitry, engineered conservatively service. trouble-free of assuring years Our packaging is the most rugged available, constructed from 16-gauge aluminum or stainless steel, glass epoxy, plug-in PC Boards.
IV-C. Troubleshooting Symptom Cause Remedy System non-operable; power switch not lit A. loss of AC power or B. internal fuse is blown; could be caused by power supply failure A. plug unit into dependable AC source B. replace fuse; if it blows repeatedly, bridge rectifier or other component probably shorted inside power supply. Have power supply fixed. …________________________________________________________ Circuit breaker trips repeatedly; short circuit LED remains lit A.
Symptom Feedback Cause acoutical Remedy A. check sidetone levels B. check termination (should be only one per channel) C. volume too high at one station D. two or more speaker stations have mics on at once; speak one at a time (per channel) E. speaker volume up too high at station with gooseneck mic *Power supply's 10-ohm resistor is opened when the system ground comes in contact wtih something "hot," with respect to the station's earth ground.
410023 410024 RES CF1/4W 51 56K OHMS RESCF1/4W 5% lOOK OHMS 410025 410028 410030 410031 410032 RES RES RES RES RES 410033 410035 410036 410036 410039 410040 410041 410055 410058 410059 410063 410065 410066 410067 410071 410082 410084 410085 410086 410089 410096 410097 410104 470019 480000 RES CF 1/4W 5% 330K OHMS RES CF1/4W 52 1.8K OHMS RES CF 1/4W 5S 6.8K OHMS 82 OHMS RES CF1/4W S1 RES CF 1/4W Sl 47 OHMS RES CF1/4N S1 2.7K OHMS RES CF 1/4W 51 1.2K OHMS RES CF1/4W ST 1.
PIN 150027 170059 210132 410007 410013 470019 510039 CAEIOUF ELECTROLYTIC 16V R.L. FECREVISED 4 tH SERIES ADJUSTMENT PCIE 20 PIN RIA HEADER AMPII-97563-0 AMP RES CF1/4W 51 220 OHMS RES CF1/4W S1 4.7K OHMS REV 50K TRIM POT V NT6. PIHERIPT-IOH-50K SIT MINI PIANO DIP SWITCH GRAYHILL 176PS504 C103 C104 4 I I 4 4 4 2 3101 R203 R204 P104 5102 C102 C101 R201 R207 R205 R202 R205 R206 P10N P102 PlOt S101 ASY 400 SERIES PROGRAM INTERRUPT REV.
F/N 150048 210013 240015 240020 250054 250247 250252 250261 280053 280054 280067 390010 39Q011 410012 410026 470020 500029 510002 510006 510028 510041 520028 IOOPF IKV 20% RF CAP CAD AAA SW'D4M CONNECTOR ROSANIR6-67-0-DC-ML 125 1/2 N//IS SHAFT KNB AAA BUTTON FOR C&K SWITCH I8121 KNB RED 3 INCH SPEAKER SCREEN AAA MET MS-400A FRONT PANEL HORZ.
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