CLEAR-COM ENCORE
MS-704 FOUR-CHANNEL MAIN STATION
RM-704 FOUR-CHANNEL REMOTE STATION
INSTRUCTION MANUAL
MS-704/RM-704 Four-Channel Main/Remote Stations Instruction Manual
© 2007 Vitec Group Communications
All Rights Reserved
Part Number 810345Z Rev. 2
Vitec Group Communications, LLC
850 Marina Village Parkway
Alameda, CA 94501
U.S.A
Vitec Group Communications
7400 Beach Drive
Cambridge Research Park
Cambridgeshire
United Kingdom
CB25 9TP
Vitec Group Communications
Room 1806, Hua Bin Building
No. 8 Yong An Dong Li
Jian Guo Men Wai Ave
Chao Yang District
Beijing, P.R. China 100022
Clear-Com is a registered trademark of Vitec Group Communications.
The Clear-Com Logo is a registered trademark of Vitec Group Communications.
CONTENTS
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
The Clear-Com Concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Understanding the MS-704/RM-704 Main and Remote Stations . . . . . . . . . 1-2
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Intercom Power Status Lights (MS-704) . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Selecting Microphones and Enabling the Speaker . . . . . . . . . . . . . . . . . 1-5
Listening to Intercom Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Talking on Intercom Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
The All-Talk Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Monitoring Main Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Sending and Receiving Call Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Linking Intercom Channels Together (MS-704) . . . . . . . . . . . . . . . . . . 1-6
The Announce Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Remote Mic Kill Function (MS-704) . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Hidden Front Panel Options and Adjustments . . . . . . . . . . . . . . . . . . . . . 1-7
DIP Switch Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Hidden Adjustment Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Rear Panel Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Intercom Line Termination (MS-704) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Short-Circuit and and Overload Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Summary of Front-Panel Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Installation Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Intercom Line Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Line Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Fail-Safe Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Connecting Intercom Channels on RM-704 . . . . . . . . . . . . . . . . . . . . . 2-4
Power Distribution and Short Circuit Protection. . . . . . . . . . . . . . . . . . . . 2-5
Intercom Cable Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Portable Installation Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Permanent Installation Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Ground Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Physical Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Description of Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Headset Connector (Front Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Panel Mic Connector (Front Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Intercom Line Connectors (Rear Panel). . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Program Input (Rear Panel). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Announce Output (Rear Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
IFB/Hot Mic (Rear panel, 1/4 inch Phone Jack) . . . . . . . . . . . . . . . . . . . 2-10
Accessory (Rear Panel, DB-15F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
i
Internal Option Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
IFB Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
Run/Test Mode Jumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
Program Audio Feed to Announce Output Jumper . . . . . . . . . . . . . . . 2-12
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
MS-704 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
RM-704 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
TECHNICAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
MS-704/RM-704 Four-Channel Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
LIMITED WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-I
Warranty Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-i
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-i
Warranty Repairs and Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-ii
Non-Warranty Repairs and Returns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-ii
Extended Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-ii
Service Contract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-iii
Liability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-iii
ii
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
Please read and follow these
instructions before operating
this product.
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordance with the
manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves,
or other apparatus (including amplifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A
polarized plug has two blades, with one wider than the other. A
grounding-type plug has two blades and a third grounding prong. The wide
blade or the third prong are provided for your safety. If the provided plug
does not fit into your outlet, consult an electrician for replacement of the
obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at
plugs, convenience receptacles, and the point where they exit from the
apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with the cart, stand, tripod, bracket, or table specified by the
manufacturer, or sold with the apparatus. When a cart is used, use caution
when moving the cart/apparatus combination to avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or when unused for long
periods of time.
14. Refer all servicing to qualified service personnel. Servicing is required when
the apparatus has been damaged in any way, such as power-supply cord or
plug is damaged, liquid has been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to rain or moisture, does not
operate normally, or has been dropped.
15. WA RN I NG : To reduce the risk of fire or electric shock, do not expose this
product to rain or moisture.
Please familiarize yourself with the safety symbols in Figure 1. When you see
these symbols on this product, they warn you of the potential danger of electric
shock if the main station is used improperly. They also refer you to important
operating and maintenance instructions in the manual.
MS-704/RM-704 Four-Channel Main/Remote Stations
iii
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
This symbol alerts you to the presence of uninsulated dangerous
voltage within the product's enclosure that might be of sufficient
magnitude to constitute a risk of electric shock. Do not open
the product's case.
This symbol informs you that important operating and maintenance instructions are included in the literature accompanying
this product.
Figure 1: Safety Symbols
EMC AND SAFETY
The MS-704 and RM-704 stations meet all relevant CE, FCC, UL (MS-704
only), and CSA specifications set out below:
EN55103-1 Electromagnetic compatibility. Product family standard for audio,
video, audio-visual, and entertainment lighting control apparatus for
professional use. Part 1: Emissions.
EN55103-2 Electromagnetic compatibility. Product family standard for audio,
video, audio-visual, and entertainment lighting control apparatus for
professional use. Part 2: Immunity.
UL 60065-7, CAN/CSA-C22.2 No.60065-3, IEC 60065-7 Safety
requirements.
And thereby compliance with the requirement of Electromagnetic
Compatibility Directive 2004/108/EC and Low Voltage Directive 2006/95/EC
This device complies with Part 15 of the FCC Rules. Operation is subject to
the following two conditions: (1) this device may not cause harmful
interference, and (2) this device must accept any interference received,
including interference that may cause undesired operation.
iv
MS-704/RM-704 Four-Channel Main/Remote Stations
1
Clear-Com manufactures a
wide variety of both portable
and fixed installation units.
All are compatible with each
other.
OPERATION
INTRODUCTION
Congratulations on choosing this Clear-Com product. Clear-Com was
established in 1968 and remains the market leader in providing intercoms for
entertainment, educational, broadcast and industrial applications. The
ruggedness and high build-quality of Clear-Com products defines the industry
standard. In fact, many of our original beltpacks and main stations are still in
daily use around the world.
We recommend that you read through this manual completely to better
understand the functions of the MS-704 and RM-704. If you encounter a
situation or have a question that this manual does not address, contact your
dealer or call Clear-Com directly. Our applications support and service people
are standing by to assist you. (Refer to Chapter 5,“Warranty” for contact
information.) Thank you for selecting Clear-Com for your communications
needs.
THE CLEAR-COM CONCEPT
Clear-Com is a closed-circuit intercom system that consistently provides
high-clarity communication in high-noise and low-noise environments. A basic
system consists of a single- or multi-channel power supply or main station
connected to various single- or multi-channel remote stations, such as beltpacks
and loudspeaker stations.
Clear-Com manufactures a wide variety of both portable and fixed-installation
units. All are compatible with each other. Clear-Com intercom systems can also
interface with other communication systems and devices.
Clear-Com is a distributed amplifier system; each main and remote station
houses its own mic preamplifier, headset or speaker power amplifier, and
signaling circuitry. Stations bridge the intercom line at a very high impedance
and place a minimum load on the line. The audio level always remains constant,
and does not fluctuate as stations leave and join the network. Low-impedance
mic input lines and specially-designed circuitry make Clear-Com channels
virtually immune to RFI and dimmer noise.
Clear-Com stations are interconnected with two-conductor, shielded
microphone cable. Portable stations are connected with two conductor cables
with 3-pin XLR connectors. One wire carries the DC power from a main station
or power supply to all remote stations, and the other wire carries 2-way (duplex)
audio information. The shield acts as a common ground. One termination (per
channel) is needed throughout the intercom network, and is usually located in
the main station or power supply.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
1-1
Clear-Com main stations, power supplies and certain remote stations each have
an auxiliary program input with its own volume control, which allows an
external audio source to be fed to the intercom system.
Visual signal circuitry (call lights), a standard feature on all main and remote
stations, allows the user to attract the attention of operators who have removed
their headsets.
Short
CH.A
CH. B
CH. C
CH. D
MS-704
RM-704
MS-704
Panel Mic
Headset
(Off)
(Default)
On
Sidetone
Adjust
Panel Mic
Gain
Panel Mic
Headset
(Off)
(Default)
On
Sidetone
Adjust
Panel Mic
Gain
TO PREVENT
WARNING:
FIRE OR SHOCK HAZARD DO NOT
EXPOSE THIS EQUIPMENT TO RAIN
OR MOISTURE.
TO PREVENT
CAUTION:
ELECTRIC SHOCK DO NOT
REMOVE COVER. NO USER
SERVICEABLE PARTS INSIDE.
REFER TO QUALIFIED SERVICE
PERSONNEL.
Mic On
Announce
AllTalk
Panel
Link On
Headset
Mic Select
Remote
Mic Kill
HS
BCD
Lim
Program
Interrupt
Mic On
Mic Select
HS
BCD
Lim
Program
Interrupt
Program
DA
D
C
C
B
DA
B
C
A
B
Talk Latch
Auto-Talk
Auto-Call
Disable
/Listen
Announce
AllTalk
Panel
Headset
Program
DA
D
C
C
B
DA
B
C
A
B
Level
Talk Latch
Auto-Talk
Auto-Call
Disable
/Listen
Listen
Talk
Call
BCD
A
Pgm
Null
Listen
Null
Listen
Level
Program
On/Off
BC
Program
On/Off
Channel B
ChannelA
Listen
Talk
Call
DA
Pgm
Null
Listen
Null
Listen
Channel B
ChannelA
Channel DChannel CChannel BChannel A
Listen
Listen
Talk
Call
Pgm
Null
Listen
Channel C
Listen
Talk
Call
Pgm
Null
Listen
Channel C
Volume
Talk
On
Off
Call
Speaker
(Short)
Long
BCDA
Pgm
Pgm
Null
Listen
Line
Length
Channel D
Channel DChannel CChannel BChannelA
Listen
Volume
Talk
On
Off
Call
Speaker
(Short)
Long
BCDA
Pgm
Pgm
Null
Listen
Line
Length
Channel D
Figure 1-1: MS-704 and RM-704 Front Panels
On
Off
Channel A
Term
Channel C
Output: 30V, 1.2A Continuous, 2A Peak
On
Off
Hot Mic/IFB
Figure 1-2: MS-704 Rear Panel
Channel B
Channel D
4-Channel
Main Station
MS-704
4-Channel
Remote Station
RM--704
On
Off
Program In
Term
On
Off
Auxiliary
Announce Out
1-2
Figure 1-3: RM-704 Rear Panel
UNDERSTANDING THE MS-704/RM-704 MAIN AND REMOTE STATIONS
The MS-704 and RM-704 intercom stations are four-channel
microprocessor-controlled stations intended to work with other Clear-Com
party-line products. Both stations have a speaker, provisions for installing a panel
microphone, and a headset connector.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
The MS-704 is a four-channel main station that contains a no-fail system power
supply. The RM-704 is a four-channel remote station intended to be powered
from the intercom line.
The following is a list of features found in the MS-704 and RM-704 intercom
stations:
• MICROPROCESSOR CONTROL: Most aspects of station operation are
under microprocessor control.
• REMOVABLE ACCESS PANEL: A removable access panel allows access to
most controls and option DIP switches.
• INDIVIDUAL CHANNEL CONTROLS: Each channel has individual
talk, listen, and call pushbuttons for each channel.
• MOMENTARY/LATCHING TALK BUTTONS: The talk buttons have a
momentary and latching action depending on how the button is used. The
latching function can be defeated with DIP switches.
• INDIVIDUAL CHANNEL ADJUSTMENTS: Each channel has
individual listen level controls, channel null adjustments, and program feed
level controls.
• MULTIPLE PROGRAM INPUTS: Multiple program inputs are provided
for local station monitoring and program feed to intercom lines for local
talent cuing (IFB).
• INTERNAL IFB (IFB - Interrupt Foldback of program feeds): Program
can be fed to each channel and interrupted (IFB) when a talk function is
active or when a call signal is received on that channel. An internal jumper
determines whether the IFB function is talk- or call-signal activated.
• LINK FUNCTION (MS-704): The MS-704 has a link function that places
all channels into a common party-line at the push of a single button.
• ALL-TALK: An all-talk button allows instant access to all channels.
• ANNOUNCE FUNCTION: An announce button allows external paging.
A set of relay contacts is provided to control an external system.
• PROGRAM FEED OVER STAGE ANNOUNCE: An internal jumper
allows the main program feed to be fed to the stage announce output. The
program is automatically interrupted when the announce button is pressed.
• MIC ON/OFF SWITCH: A separate mic on/off push-button allows
turning the microphone off without upsetting the setting of talk switches.
• REMOTE MIC KILL SWITCH (MS-704): Front-panel switch allows you
to turn off all latched talks on remote stations and beltpacks.
• EXTERNAL MIC ON/OFF INPUT: An external logic input allows the
mic on/off function to be switched remotely.
• EXTERNAL IFB and HOT MIC OUTPUT: A rear panel jack provides
direct connection to Clear-Com’s external IFB system such that the station’s
microphone can be used in the external IFB system. A buffered unswitched
output of the selected microphone is also available.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
1-3
• SPEAKER ON/OFF SWITCH: The speaker may be turned on and off with
a front panel switch.
• SPEAKER DIMMING: Whenever a talk is active, the speaker output is
dimmed approximately 6 dB to prevent feedback.
• PANEL MIC GAIN: The preamplifier for the panel microphone has a gain
trim adjustment to allow field trimming. Adjustment of the panel
microphone gain also varies the frequency response of the preamplifier to
compensate for feedback when the microphone is used up close.
• POWER SUPPLY WITH SHORT CIRCUIT PROTECTION: The
MS-704 features redundant powering to remote stations by providing
separate short-circuit-protected power sources to each of the four intercom
lines. A short on one intercom line will not bring the whole system down.
Short circuit indicators are provided on the front panel for each channel.
• HEADSET AUDIO LIMITER: The headset audio limiter restricts the
maximum audio level heard in the headset to protect the hearing of the user.
You can turn this feature on or off with one of the front-panel dip switches.
OPERATION
Once installed and operational, the MS-704 and RM-704 intercom stations are
easy to operate. The following sections describe normal operation of the units,
use of controls available under the access panel, and abnormal operation of the
power distribution system.
Some of the following functions are exclusive to the MS-704 and are marked as
such.
NORMAL OPERATION
Normal operation of the MS-704 and RM-704 requires access only to the front
panel controls. The following is a brief description of how to use the front panel
controls in day-to-day operation.
There are option DIP switches and adjustment controls behind the access panel
in the lower portion of the front panel. To gain access to the switches and
controls, pull on the two latches on either end of the access panel and remove it.
This section discusses the following subjects:
• Intercom power status lights
• Selecting microphones and enabling the speaker
1-4
• Listening to intercom channels
• Monitoring main program
• Talking on intercom channels
• The all-talk function
• Sending and receiving call signals
• Linking intercom channels together (MS-704)
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
• The announce function
Intercom Power Status Lights (MS-704)
The four red short lights are failure indicators for each of the four intercom lines.
These lights will assist in locating a shorted or overloaded channel. Within as
little as ½ second of automatically cutting off power to an overloaded intercom
line, the MS-704 will attempt to turn power on again. This allows momentary
short or overload conditions to clear automatically. Shorts are normally caused by
miswiring or damaged cables. Overloads are generally caused by connecting too
many beltpacks and stations to an intercom line.
Clear-Com’s advanced fail-safe design can sense the difference between a short or
an overload to optimally protect itself. Power is restored in as little as ½ second,
depending upon whether there was a single or multiple short or overload. The
other channels continue to operate normally. The MS-704’s advanced fail-safe
circuit will bring the power back up even under full load conditions. Front-panel
lights indicate a fault on any of the four channels.
When the station is first turned on, all four short lights are normally off.
Selecting Microphones and Enabling the Speaker
To select the desired microphone, move the microphone select switch to the
appropriate position: either “panel” or “headset.”
The mic on pushbutton allows turning the microphone on or off. The mic on
pushbutton lights blue when the microphone is active.
The microphone will be turned on automatically whenever a talk function is
activated as it is assumed that you wish to talk. If one or more talks are active, you
may turn the microphone off without unlatching the active talks.
The speaker may be turned on and off with the speaker switch.
Listening to Intercom Channels
To listen to an intercom channel, press the listen button for the desired channel.
The listen button lights green to indicate that the listen function is on.
The listen level control (below the call button) for that channel is usually set to
full on position and the listening volume is set by the intercom volume control to
the left of the speaker.
If several channels are being listened to at the same time, it might be desirable to
adjust the individual listen levels of each channel for the desired mix.
Talking on Intercom Channels
To talk on an intercom channel, press the desired talk button. Pressing and
holding the button will cause the function to be active only while the button is
held (momentary). Pressing and releasing the button quickly will cause the
function to latch on if it was off or turn off if it was on (latching).
The latching function can be defeated on an individual channel with an option
DIP switch beneath the access panel (latch disable DIP switch).
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
1-5
The button will be illuminated blue when the talk function is off and amber
when the talk function is on.
Another option allows the automatic setting of a listen function whenever a talk
is active (auto-listen DIP switch) for each channel.
The All-Talk Function
Pressing the button marked all talk sends the selected microphone to all channels
while the button is pressed (momentary only). This button lights amber when
pressed.
Monitoring Main Program
The main program input is the one on the XLR connector on the rear panel. To
listen to the main program in the speaker or headphone, adjust the program level
control just below the link and all talk pushbuttons.
Sending and Receiving Call Signals
To s en d a call signal on an intercom channel press the call button for that
channel. This is a momentary function.
If the auto-call option is selected for that channel, activating a talk button will
also send a call to that channel.
Receiving a call signal is indicated by a flashing red call button.
Linking Intercom Channels Together (MS-704)
A pushbutton allows the connecting of intercom channels B, C, and D to
channel A. The link pushbutton is latching in action. The link button
illuminates amber when all channels are linked together. In the latched position,
the entire station operates as one party line.
Ta l k and listen buttons are non-functional on channels B, C, and D when they
are linked to channel A.
The Announce Function
A single pushbutton sends the active microphone’s audio to the announce output
on the rear panel. Any active talks are disabled while the announce button is
held. The announce button illuminates amber when held. Ta l k and listen latches
are not reset, but the microphone’s audio does not go to the intercom line while
the announce function is active. A set of relay contacts are activated to control
some external device.
There is an option which allows program audio to be fed to the announce output.
If this option is enabled, the announce pushbutton interrupts this audio when it
is pressed. Program audio feed to the announce output is selected by setting
jumper J11 on the main board to the on position.
1-6
Remote Mic Kill Function (MS-704)
When you press the remote mic kill pushbutton, the talk function shuts off for
every beltpack on all four channels. If the talk functions of a large number of
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
beltpacks have inadvertently been left activated, incidental noise and talking can
make it difficult or impossible to communicate on the party line intercom. The
remote mic kill button can be pressed to quiet the line in this situation. Those
needing to communicate can then set their talk functions to on as needed.
Note: The remote mic kill button only functions if the MS-704 main station is
powering all of the stations in the system. Pressing the button
momentarily interrupts power to the other beltpacks and stations in the
system. If there are other power supplies or main stations in the system,
then the remote mic kill switch cannot interrupt power and therefore
cannot work.
HIDDEN FRONT PANEL OPTIONS AND ADJUSTMENTS
This section describes the option DIP switches and various adjustment controls
behind the access panel on the front panel. These option switches and controls
are usually set and not used in daily operation of the unit.
To gain access to these controls, pull on the two latches on either end of the
access panel and remove it.
DIP Switch Options
The unit is shipped with all DIP switches, except the Headset Audio Limiter, in
their default positions (up). The Headset Audio Limiter dip switch is shipped in
the down (on) position.
The following functions are enabled with DIP switches:
• HEADSET AUDIO LIMITER: The HS dip switch turns the headset audio
limiter on or off. Unless an especially high volume is needed, this switch
should be left in the on position to protect the hearing of the user.
• INTERRUPT ENABLE: Three DIP switches (B, C, and D) enable the
program interrupt function on channels B, C, and D. Program interrupt is
not available on channel A.
• AUTO-CALL: Four DIP switches (one for each channel) enable
automatically sending a call signal whenever a talk is active on the enabled
channel.
• AUTO-TALK/LISTEN: Four DIP switches (one for each channel) enable
automatically setting the listen function whenever a talk is active on the
enabled channel.
• TALK LATCH DISABLE: Four DIP switches (one for each channel) disable
the latching action of the selected channel.
• PROGRAM ON/OFF: Four DIP switches (one for each channel) enable
feeding the main program input to the selected intercom channel. The main
program input is the one on the XLR-3F on the rear panel.
The other four program inputs in the auxiliary connector feed their respective intercom channels all of the time. The only way to turn off the Auxiliary
feed to a channel is to turn its individual control off.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
1-7
• LINE LENGTH: Four DIP switches (one for each channel) allow the
optimization of the nulling circuitry for each channel. The default (up
position) is for lines less than 400 ft. (122 m). The down position is for lines
longer than 400 ft. (122 m).
Hidden Adjustment Controls
Various adjustments are available beneath the front access panel.
• PANEL MIC GAIN: This control trims the panel microphone preamplifier
gain to compensate for different uses of the station.
The unit is shipped from the factory in the minimum gain position (fully
counter-clockwise). This level matches the headset microphone level when
the panel microphone is worked up close. Raising the gain from the factory
setting should be done carefully, as too much gain will increase the background noise in the intercom making it unusable.
• CHANNEL NULL ADJUST: The screwdriver-adjustable control beneath
each talk pushbutton marked null allows nulling of the hybrid circuitry
associated with each listen channel.
The amount of null in the listen circuitry varies with the length of the intercom line. Adding or removing stations and intercom cable will change the
null. For optimum performance, the null control will need to be adjusted
each time there is some change in the intercom line wiring.
If a panel microphone and speaker is being used, the setting of the null control is critical to prevent feedback.
To a d j u s t th e null control on a given channel:
1. Tu rn t he sidetone adjust control just below the headset connector to
minimum.
2. Set a talk to the channel to be adjusted or send some program to the
channel and adjust the null control for the channel for minimum level in
the headphone. If the headset microphone is being used, hum or gently
scratch it for a continuous signal source to null on. If a good null is not
attainable, switch the long/short DIP switch for the channel (to the far
right of the hidden adjustments) to its opposite setting. Use the setting
that produces the best results.
3. Repeat the adjustment for all four channels on the station.
4. Adjust the sidetone adjust control for the desired amount of sidetone in
the headset.
• CHANNEL PROGRAM FEED LEVEL: Beside the null control for each
channel there is a control marked PGM, which adjusts the amount of
program being sent to that channel.
Each channel has two program sources:
1. The main program that is input from the rear panel XLR connector may
be enabled for a given channel with the program on/off DIP switches for
the channel.
1-8
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2. The auxiliary input connector has four individual program inputs for
each channel. These inputs cannot be disabled with front-panel DIP
switches.
REAR PANEL OPTIONS
This section describes the switches on the rear panel. These switches and controls
are usually set and not used in daily operation of the unit.
INTERCOM LINE TERMINATION (MS-704)
The MS-704 has switch-selectable intercom line termination networks. The
RM-704 is a remote station and therefore does not have terminating networks
available. If more than one MS-704 (or any other master station) is installed on
the same intercom line, then all of the terminations in all of the stations except
one must be disabled.
CAUTION: If the link function is to be used on an MS-704 and there is more than
one MS-704 in the system, it can only be used on the unit that provides
termination.
The terminations are enabled or disabled with switches on the rear panel. Each
channel is marked clearly on the panel. Set the switches to the off position to
disable the terminations in the station. The MS-704 is shipped from the factory
with all four lines terminated.
SHORT-CIRCUIT AND AND OVERLOAD CONDITIONS
If a short circuit condition appears on any of the four intercom lines, the sense
circuitry for that line will disconnect the DC power to that line only and the red
“short” light for that channel will be on. After as little as 1/2 second, the MS-704
will attempt to turn power on again. This allows momentary short or overload
conditions to clear automatically.
If the red “short” light remains after repeated automatic or manual attempts to
restore power, then there is either a short on that intercom line or too many
intercom stations have been connected to that intercom line. In this case, unplug
the intercom line connected to the affected channel and its red “short” light
should go out. This indicates that there is a short in that line. Follow that
intercom line and break it apart in several places while it is plugged into the
station to isolate the section of line that is shorted.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
1-9
SUMMARY OF FRONT-PANEL LIGHTS
Table 1 summarizes the meaning of various front-panel key colors.
Key “On” State “Off” State Momentary or Latching
Microphone Blue Off Latching only (activates
automatically in
conjunction with some
other features, like “talk”)
Listen Green Off Latching only (can be set
to activate automatically
with “talk”)
Talk /Power On Amber Blue (indicates
that the station
is receiving
power, but the
“talk” feature is
off)
Call Red
(flashing)
Announce Amber Off Momentary only
All-Talk Amber Off Latching only
Link-On Amber Off Latching only
Remote
Microphone
Kill
Short/Overload Red Off N/A
Note: Note: To “latch” (or “lock”) a button to “on,” quickly press it once. The
button is “locked” to “on” for hands-free use. Pressing the button again
releases the latch. Otherwise when you press and hold a button the
feature switches on, and when you release the button the feature switches
off. This is called “momentary” use.
Amber Off Momentary only
Off Momentary only
Both
1-10
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2
INSTALLATION
This chapter discusses how to install the MS-704 and RM-704 intercom stations
in an intercom system.
INSTALLATION OVERVIEW
This section describes the Clear-Com concept of intercom line interconnection.
The following subjects are discussed:
• Intercom line connection
• Line termination
• Station powering
• Cable considerations
Intercom Line Connection
The MS-704 provides two male XLR-3 connectors for each intercom line.
The RM-704 provides a male and female XLR-3 connector for each intercom
line, which are looped through.
Line Termination
The fundamental concept of the Clear-Com party-line intercom is that all
stations provide high impedance into a single 200-ohm system termination.
CAUTION: An intercom line must be terminated. Care must be taken not to
“double”-terminate a line. All unused intercom inputs must be
terminated to keep the line drive circuits stable.
The MS-704 provides switchable terminations of the intercom lines. Clear-Com
main stations and power supplies provide switch-selectable termination networks
on all intercom output lines. It is up to the user to determine where the
termination will be provided. An unterminated line will cause excessive levels,
possible oscillation of line drivers, and severe imbalance of hybrid null networks.
A double- or multiple-terminated line will cause low levels and severe unbalance
of hybrid null circuits.
Switching of the termination on and off on the MS-704 is with back panel
switches. The MS-704 is shipped from the factory with all four lines terminated.
USING THE LINK FUNCTION: The link function in the MS-704 connects
the four party lines together. In doing so, it also removes the terminations from
channels B, C, and D such that the new party line on channel A has only one
termination when link is activated. If there is more than one MS-704 in a system,
the link function can only be used at the station where the terminations are set
on.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2-1
FAIL-SAFE POWER
An intercom power supply has special needs that are not met by traditionally
designed power supplies. An intercom power supply must work in adverse
conditions such as low AC line voltage, momentary shorts on the DC power
lines to the stations, and excessive peak loads during “power-on”conditions. The
following features are incorporated into the MS-704’s power supply:
• AUTOMATIC SHORT CIRCUIT PROTECTION: The MS-704’s
internal power supply checks each channel for a short or current overload. If
it detects a short the power supply will shut down that channel. A short
duration short circuit will not cause the power supply to interrupt power.
• AUTOMATIC OVERLOAD PROTECTION: The MS-704’s internal
power supply senses the difference between shorts and overloads. If an
overload is detected the power supply will shut down that channel. An
overload lasting a short period will not cause the power supply to interrupt
power.
• AUTOMATIC POWER RESTORE: The MS-704’s internal power supply
senses the difference between short-term and long-term shorts and overload
conditions. After the first few times a short or overload occurs, the power
supply will try to restore power after only 0.5 seconds. If the short or
overload persists or occurs repeatedly, the power supply will take
progressively longer (to a maximum of 20 seconds) to try to restore power.
This protects the power supply from damage due to overheating. Once the
short is removed, the channel will recover, even under a full load condition.
The automatic power restore times are shown in the following chart:
20
19
18
17
16
20
Number of
seconds to
restore
20
10
14
121314 15
11
15
10
7
5
0.5
0
2
0
1
4
2
67
4
3
5
Number of recent shorts or overloads
9
8
Figure 2-4: Automatic Power Restore Times
• INDIVIDUAL CHANNEL SHORT CIRCUIT PROTECTION: Each
individual channel is separately overload and short circuit protected and may
draw as much as 1.2 amperes, though the total to both channels is limited to
2-2
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2 amperes. A short on any one intercom line will not bring the whole system
down.
Note: Power supply lines connected together at remote stations will disable
the individual channel short circuit protection feature.
• FRONT PANEL “SHORT” LIGHTS: There are four short lights on the
front panel (one for each channel). The short lights illuminate steadily when
an overload or short condition is detected. They blink if power to a channel
has been shut off as a result of an overload or short.
• PARALLELING MULTIPLE POWER SUPPLIES: Multiple power
supplies can be paralleled to increase system capacity. The MS-704’s internal
power supply will automatically detect the actions of other power supplies
during overloads and short circuits to restore power as quickly as possible.
• MULTI-CHANNEL REMOTE STATIONS MAINTAIN THE POWER
LINE ISOLATION. Internal jumpers in the RM-704 allow you to select
non-isolation if needed. See the Operation chapter of this manual for more
information.
• LOW NOISE CIRCUITRY: The direct current outputs of the MS-704’s
internal power supply contain very little hum and noise. The power supply
does not contribute to audible noise in the remote stations and beltpacks.
• CONNECTION TO AC MAINS: The AC power line supplies power to
the MS-704’s internal power supply. The power supply will accept any line
voltage between 100 and 240 VAC at 50-60 Hz. It will automatically adjust
to the line voltage. There is no need for a voltage selector switch or an
external fuse. The unit draws a maximum of 60 VA of power from the AC
line. Clear-Com power supplies can be paralleled to increase the number of
remote stations that can be operated in a system.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2-3
FAIL SAFE POWER DISTRIBUTION SCHEME
WITH SINGLE-CHANNEL REMOTE STATIONS
MS-704 Main Station
2 Amp
Power
Supply
R
R
R
R
BELT
PAC K
BELT
PAC K
BELT
PAC K
BELT
Ch A
Ch B
Ch C
Ch D THE 4 POWER LINES
+30 Volts
for each
Intercom
Line
PAC K
Wall Station
Wall Station
Wall Station
Wall Station
BELT
PAC K
BELT
PAC K
BELT
PAC K
BELT
PAC K
ARE NOT CONNECTED
Wall Station
Wall Station
Wall Station
Wall Station
Figure 2-5: Stations Powered by Individual Channels
The illustration above shows the proper power wiring of a system powered by a
single MS-704. The remote stations connected to each channel are powered from
the intercom cable for that channel. In the case above, a short on any one line
will only take that channel down.
It is assumed that none of the power channels are connected together in the
external system wiring. However, if the power channels in a multiple-channel
remote station have been bridged by connecting the internal jumpers, those
channels would now have their power connected together. The system would still
work except that a short circuit on any of the connected channels would cause
them all to short circuit, thus taking more of the system down with a single short
circuit.
2-4
Connecting Intercom Channels on RM-704
Internal jumpers in the RM-704 allow you to defeat the power-channel isolation
of the unit, as described in the following procedure.
To connect two or more RM-704 channels together:
1. Please observe anti-static procedures. The circuit cards can be damaged by
static electricity. Please ground yourself and tools before touching any circuit
cards.
2. Remove the cover of the RM-704.
3. On the main circuit board, locate the J16 six-pin jumper.
The jumper is located on the center leftmost portion of the circuit card when
viewed from the front of the station. The label “J16” appears next to it.
Three jumper plugs are stored, unconnected, on the pins.
4. To connect two channels, lift one of the jumper plugs off of the pins, and
place it in the proper position, as shown in Figure 2-6.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
J16
5. Continue placing pins until all desired channels are connected.
6. Replace the cover of the RM-704.
FAIL SAFE POWER DISTRIBUTION SCHEME
WITH MULTI-CHANNEL REMOTE STATIONS
MS-704 Main Station
2 Amp
Power
Supply
R
R
1
4
5
Placing jumper plug over pins 1 and 2 connects channels A and B
2
3
Placing jumper plug over pins 3 and 4 connects channels B and C
6
Placing jumper plug over pins 5 and 6 connects channels C and D
Figure 2-6: J16 Six-Pin Jumper
+30 Volts for each
Ch A Power
Ch B Power
Ch C Power
Ch D Power
Intercom Line
TO
SYSTEM
R
Belt
R
Station
Electronics
Pack
Other
Remote
Stations
RM-704 Remote
Station
Figure 2-7: Stations Powered by Multiple Channels
The illustration above shows the power wiring of a system powered by a single
MS-704. An RM-704 is connected to all four power lines through the intercom
line connections. However, the blocking diodes in the RM-704 prevent a short
circuit on one line affecting the others. Other single channel remote stations are
also connected to individual channels.
POWER DISTRIBUTION AND SHORT CIRCUIT PROTECTION
Depending upon how many shorts or overloads a channel has experienced
recently, the MS-704 will attempt to turn power on again within 0.5 to 20
seconds of automatically cutting off power to an overloaded channel. This allows
momentary short or overload conditions to clear automatically. If the MS-704
cuts power off to one or both channels, it will indicate which channel is affected
by blinking the red short light(s) corresponding to these channel(s). This light
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2-5
will assist in locating the shorted or overloaded channel. Shorts are generally
caused by miswiring or damaged cables. Overloads are generally caused by
connecting too many beltpacks and stations to a channel.
The current requirements of Clear-Com remote stations and beltpacks vary with
model and use. A station that is simply on and idling in the circuit may draw only
a small amount of current.
The MS-704 provides DC power to operate Clear-Com beltpacks and remote
stations. The power is distributed between the four channels and will support
up to 40 RS-601 beltpacks or 10 speaker stations or 12 headset stations.
INTERCOM CABLE CONSIDERATIONS
The Clear-Com intercom line is intended to run on a shielded pair cable. One
conductor carries audio, the other conductor carries the DC power for remote
stations. The shield is used for ground return for audio and power. When
choosing interconnect cable, keep the following considerations in mind:
1. DC resistance of the ground or common conductor affects crosstalk. For runs
longer than 500 ft. (152.5 m) do not use wire smaller than 20 gauge.
2. The capacitance of the interconnect cable affects system frequency response
and sidetone stability. Total capacitance should not be greater than 0.25 uF.
PORTABLE INSTALLATION CABLE
Practical cable for portable system interconnections is flexible, two-conductor,
shielded microphone cable. We suggest you use BELDEN #1800F (24 gauge).
For runs longer than 500 ft. (152.5 m) use a 20 gauge cable or larger (BELDEN
#8412).
PERMANENT INSTALLATION CABLE
Vinyl-jacketed shielded pair is the cable of choice for permanent installations.
Use a low-capacitance 20 gauge wire for runs under 500 ft. (152.5 m). We
suggest you use BELDEN #8762. For runs longer than 500 ft. (152.5 m), use an
18 gauge cable (BELDEN #8760). Placing the cable in conduit is recommended
but not necessary.
Multi-pair cable that is individually shielded is acceptable for use in
multi-channel systems. For cross-talk considerations, the shields must be tied
together on both ends of the cable to produce the lowest possible DC path for
ground return.
WIRING DIAGRAM
The diagram shows using a multi-pair cable to connect two stations. Note that
the power and shield wires of each channel are not connected together.
2-6
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
GROUND ISOLATION
The pin #1 ground connection of each XLR connector must also be isolated
from the chassis. Pin #1 should not be connected to the shell of the XLR
connector.
Figure 2-8: Interconnect Cable Detail
Note: The remote stations connected to each channel are powered from the
intercom cable for that channel. In the case above, a short on any one
line will only take that channel down.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2-7
RM-704
RM-704
HOT MIC/IFB
CHANNEL A
CHANNEL C
Class 2 Wiring
CHANNEL B
CHANNEL D
PROGRAM IN
AUX
ANNOUNCE OUT
MS-704
MS-704
TO
WARNING:
PREVENT
FIRE OR SHOCK HAZARD DO NOT
EXPOSE THIS EQUIPMENT TO RAIN
OR MOISTURE.
TO PREVENT
CAUTION:
ELECTRIC SHOCK DO NOT
REMOVE COVER. NO USER
SERVICEABLE PARTS INSIDE.
REFER TO QUALIFIED SERVICE
PERSONNEL.
HOT MIC/IFB
CHANNEL A
CHANNEL C
Output: 30V 1.2A Continuous, 2A Peak
On
Off
On
Off
CHANNEL B
CHANNEL D
Term
On
Off
On
Off
PROGRAM IN
AUX
ANNOUNCE OUT
Belden Cable
(4 individually shielded pairs)
Figure 2-9: Proper power wiring of a system powered by a single MS-704
PHYSICAL INSTALLATION
You can install the MS-704 and RM-704 units in a standard equipment rack, or
you can use them as stand-alone units sitting on a table or desk. For installing in
an equipment rack, the units require 3.5 in. (8.89 cm or 2RU) of rack space. The
stations are10.5 in. (26.67 cm) in depth and require at least 2.5 in. (6.35 cm)
clearance in the rear to clear connectors and cables.
DESCRIPTION OF CONNECTORS
2-8
HEADSET CONNECTOR (FRONT PANEL)
Note: The following is a description of a recommended headset.
Mic Type --- Dynamic, see technical specifications for details
Wiring:
Pin 1 --- Mic common
Pin 2 --- Mic hot
Pin 3 --- Headphone common
Pin 4 --- Headphone hot
CAUTION: Do not tie pin #1 and pin #3 together.
PANEL MIC CONNECTOR (FRONT PANEL)
Two plug-in panel microphones are available for use on the MS-704 and
RM-704. The GM-9 is 9 in. (22.86 cm) long and GM-18 is 18 in. (45.72 cm)
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
long. The microphone is of the electret type. The microphone has a built-in
¼ in. (0.64 cm) phone jack for a connector. A proprietary mating receptacle is
mounted on the station.
To install a GM-9 or GM-18 panel mount microphone, use the following steps:
1. Check the set screw in the mic mounting flange to make sure it is clear of the
threads in the bushing.
2. Screw the microphone into the bushing hand tight.
3. If desired, set the set screw on top of the bushing to lock the mic in place.
INTERCOM LINE CONNECTORS (REAR PANEL)
The MS-704 has a pair of male XLR-3 connectors for each intercom line. The
male-male pair of connectors are wired in parallel to allow connecting multiple
remote stations.
The RM-704 has a male and female pair of XLR-3 connectors for each intercom
line. The male-female connectors are wired in parallel and intended for
loop-through connection.
The pinout of the intercom connectors is as follows:
Pin 1 --- Ground (shield)
Pin 2 --- Power
Pin 3 --- Audio
PROGRAM INPUT (REAR PANEL)
A XLR-3F connector provides the main program input to the station. This input
is fed to the front panel program level control for listening in the headphones or
speaker. Optionally, it can be fed to each of the intercom lines with the option
DIP switches marked program select A-D. Another option is to feed program
audio to the announce output. This is selected by setting jumper J11 on the main
board to the on position.
Separate program inputs are also available for each channel via the accessory
DB-15 connector. Refer to the section on that connector for details.
The pinout of the program input connector is as follows:
Pin 1 --- Ground (shield)
Pin 2 --- - Signal
Pin 3 --- + Signal
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2-9
ANNOUNCE OUTPUT (REAR PANEL)
An XLR-3M connector provides the announce output from the station.
Whenever the announce button on the front panel is pressed, the selected
microphone is sent to the announce output and the announce relay is activated.
Simultaneously, if the program audio feed to the announce output is enabled, it
is interrupted by the announcement. Program audio feed to the announce output
is selected by setting jumper J11 on the main board to the on position. Refer to
the section on the accessory connector for instructions on connecting to the relay
contacts.
The pinout of the announce output connector is as follows:
Pin 1 --- Ground (shield)
Pin 2 --- - Signal
Pin 3 --- + Signal
IFB/HOT MIC (REAR PANEL, 1/4 INCH PHONE JACK)
A 1/4 in. (0.64 cm) phone jack marked IFB/Hot mic provides an output signal
from the selected microphone. This output is also intended to work with
Clear-Com’s IFB system. Consult the factory for installation instructions.
The jack connections are as follows:
Tip --- Hot mic output
Ring --- Control signal in
Sleeve --- Ground
ACCESSORY (REAR PANEL, DB-15F)
The accessory DB-15F connector on the rear panel provides auxiliary program
inputs for each channel, remote mic on/off input, line level output, and announce
relay contacts. The pin assignments of the connector are as follows:
2-10
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
Figure 2-10: Accessory Connector
• AUXILIARY PROGRAM INPUTS: Four different program inputs, one
for each channel, are provided. These auxiliary program inputs can only be
fed directly to their associated intercom line. The only controls that affect
these inputs are the PGM-level controls associated with each channel and the
internal program interrupt switch that is active if the function has been
activated with an option DIP switch and a talk is active on that channel.
These inputs are electronically balanced with a high input impedance. Refer
to the illustration above for connection of the program inputs. Pins #5 or #14
can be used for connecting shields.
• REMOTE MIC ON/OFF SWITCH: An external momentary pushbutton
switch connected to pins #5 and #13 will duplicate the action of the front
panel mic on/off switch.
• ANNOUNCE RELAY CONTACTS: A relay is provided that activates
when the announce button is pressed and its contacts are available on the
accessory connector. The relay contacts are rated for 2.0 amperes of DC
current at 24 VDC and are electrically isolated from the rest of the station.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
2-11
INTERNAL OPTION JUMPERS
There are several jumper options inside the chassis of the MS-704 and RM-704.
CAUTION: Remove AC power from the unit before removing the top cover.
The following options are available:
•IFB operation mode select
•Run/test mode jumper
• Program audio feed to announce output
IFB Mode
The MS-704 and RM-704 support two different modes of operation for the
internally generated IFB function. J10 on the main PC board (in the lower left
hand corner of the board just behind the DIP switches) selects this mode. If an
interrupt enable DIP switch is enabled for a channel, the operation will be as
follows:
• LOCAL (Talk Function Activated): Jumper between Pins #1 and #2, factory
default. When a talk is active on the channel on which the interrupt has been
enabled, the program will be interrupted for the duration of the talk.
• REMOTE (Call Signal Activated): Jumper between pins #2 and #3. When a
call is received on the channel on which the interrupt has been enabled, the
program will be interrupted for the duration of the call signal on that
channel. To cause an interrupt of the program from this station a call signal
must be sent by pressing the call button or enabling the auto-call DIP switch
option for that channel and activating a talk on that channel.
Run/Test Mode Jumper
The J2, J12, P3, and P4 jumpers on the main printed circuit board allow a
factory test mode to be invoked and should never be used for normal intercom
operation.
CAUTION: Do not move these jumpers. Moving these test jumpers may cause the
MS-704 and RM-704 not to operate. Possible damage to the product
may result.
Program Audio Feed to Announce Output Jumper
J11 on the main board allows program audio to be fed to the announce output.
This is selected by setting jumper J11 to the on position. In this mode, pressing
the announce pushbutton turns off the program audio feed to the announce
output and replaces it with audio from the selected panel or headset microphone.
The factory default position for J11 is in the off position, blocking program
audio feed from the announce output.
2-12
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
MAINTENANCE
3
INTRODUCTION
This chapter provides maintenance information, including a block diagram and troubleshooting tips.
Caution: These servicing instructions are for use by qualified personnel only. To reduce the risk of electrical shock, do not
perform any servicing other than that contained in the operating instructions unless you are qualified to do so.
MS-704 BLOCK DIAGRAM
Figure 3-11: MS-704 Block Diagram
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
3-1
RM-704 BLOCK DIAGRAM
3-2
Figure 3-12: RM-704 Block Diagram
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
4
TECHNICAL SPECIFICATIONS
MS-704/RM-704 FOUR-CHANNEL STATIONS
dBu is an absolute measurement. 0 dBu is referenced to 0.775 volts RMS
Panel Microphone Input
Input Type Electret
Input Impedance >=2K
Mic Limiter Threshold 0dBu ±3dB
Mic Limiter Range >= 20dB
Headset Microphone Input
Input Type Dynamic
Input Impedance >= 1K
Mic Limiter Threshold 0dBu ±3dB
Mic Limiter Range >= 17dB
Program Line Input
Maximum Level before Clipping >= 20dBu
Input Impedance >= 5K
Ω
Ω
Ω
Headset Output
Load Impedance >= 8
Output Impedance <= 25
Output Limiter Threshold +5dBu ± 3dB
Maximum Output Level before Distortion >= 17dBu
Speaker Output
Load Impedance >= 4
Max Output Level before 1% Distortion 20dBu ± 2dBu
Party Line Output
Off Noise < -74dBu
Output Impedance >10K
Party Line Input
Crosstalk < -60dB
Max level before Clipping >= 12dBu
Sidetone Null Capability > 25dB
Stage Announce/Balanced Line Out
Ty p e B al a nc e d
Output Impedance >= 200
Load Impedance >= 600
Ω
Ω
Ω
Ω
Ω
Ω
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
4-1
IFB/Hot Mic
Ty p e U nb a l a nc ed
Output Impedance 150
Load Impedance >= 600
Ω
Ω
Frequency Response
Panel Mic - Party Line 600 - 10KHz ± 3dB
Headset Mic - Party Line 200 - 12KHz ± 3dB
Headset Mic - Line Out 200 - 12KHz ± 3dB
Program Input - Party Line 100 - 17KHz ± 3dB
Program Input - Headset Out 200 - 10KHz ± 3dB
Program Input - Speaker Out 300 - 10KHz ± 3dB
Party Line - Headset Out 200 - 10KHz ± 3dB
Party Line - Speaker Out 300 - 10KHz ± 3dB
Max Distortion
Panel Mic - Party Line <= 0.5%
Headset Mic - Party Line <= 0.5%
Headset Mic - Line Out <= 0.5%
Program Input - Party Line <= 0.2%
Program Input - Headset Out <= 0.2%
Program Input - Speaker Out <= 0.5%
Party Line - Headset Out <= 0.2%
Party Line - Speaker Out <= 0.5%
Noise
Panel Mic - Party Line < -65dBu
Headset Mic - Party Line < -70dBu
Headset Mic - Line Out < -55dBu
Program Input - Party Line < -85dBu
Program Input - Headset Out < -60dBu
Program Input - Speaker Out < -60dBu
Party Line - Headset Out < -50dBu
Party Line - Speaker Out < -50dBu
Max Gain
Panel Mic - Party Line >= 37dB
Headset Mic - Party Line 41dB ± 2dB
Headset Mic - Hot Mic Out 55dB ± 3dB
Headset Mic - Announce Out 55dB ± 3dB
Program Input - Party Line >= -16dB
Program Input - Headset Out >= 18dB
Program Input - Speaker Out >= 24dB
Party Line - Headset Out >= 34dB
Party Line - Speaker Out >= 40dB
Min Gain
Panel Mic - Party Line <= 25dB
4-2
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
Mains Power (MS-704)
Input Voltage Range 100 - 240 VAC
Input Frequency Range 50 - 60 Hz
Input Power <= 60 VAC
Output Voltage 30 VDC ± 0.5V
Output Current per Channel (Continuous) 1.2 A
Output Current per Channel (Peak) 2 A (Do not exceed the 1.2A rating
for more than 2 seconds per 1
minute period)
Short Circuit Recovery Time (1st short) <= 0.5 sec
Short Circuit Recovery Time >= 20 shorts in 20sec) <= 20 sec
Station Capacity (MS-704)
Up to 40 RS-601 beltpacks or 10
speaker stations or 12 headset
stations distributed over all
channels
DC Power (RM-704)
Input Voltage Range 20-30 VDC
Input Current (Idle) <=165 mA
Input Current (Max) <=195 mA
Rear Panel Connectors (MS-704)
Intercom: (8) XLR-3M (2 per channel)
Announce Out: (1) XLR-3M (audio)
Program: (1) XLR-3F
Hot Mic / IFB Interface: (1) 1/4 in. (0.64 cm) phone jack
Accessory (1) DB-15F
AC Power: IEC 320 connector
Rear Panel Connectors (RM-704)
Intercom: (4) XLR-3M (1 per channel)
(4) XLR-3F (1 per channel)
Announce Out: (1) XLR-3M (audio)
Program: (1) XLR-3F
Hot Mic / IFB Interface: (1) 1/4 in. (0.64 cm) phone jack
Accessory (1) DB-15F
Rear Panel Controls
(1) Power switch (MS-704)
Front Panel Connectors
Panel Mic: (1) 1/4 in. (0.64 cm) panel
mounting jack
Headset: (1) XLR-4M
Front Panel Controls & Indicators (MS-704)
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
(1) Panel / headset mic switch
(1) Mic on button
4-3
(1) All talk button
(1) Announce button
(1) Party line link button
(4) Program
ON-OFF-INTERRUPT
DIP switches
(1) Program level control
(4) Listen adjust controls
(4) Channel null adjust controls
(4) Channel program feed adjust
controls
(4) Talk buttons
(4) Call buttons
(4) Listen buttons
(1) RMK button
(1) Speaker ON-OFF switch
(1) Speaker volume control
(4) Short LEDs
(1) Panel mic gain control
(1) Sidetone adjust control
(1) Headset audio limiter DIP
switch
(3) Interrupt enable DIP switches
(4) Auto-call DIP switches
(4) Auto-talk/listen DIP switches
(4) Talk latch disable DIP switches
(4) Line length DIP switches
Front Panel Controls & Indicators (RM-704)
(1) Panel / headset mic switch
(1) Mic on button
(1) All talk button
(1) Announce button
(4) Program
ON-OFF-INTERRUPT
DIP switches
(1) Program level control
(4) Listen adjust controls
(4) Channel null adjust controls
(4) Channel program feed adjust
controls
(4) Talk buttons
(4) Call buttons
(4) Listen buttons
(1) Speaker ON-OFF switch
(1) Speaker volume control
(1) Panel mic gain control
(1) Sidetone adjust control
(1) Headset audio limiter DIP
switch
4-4
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
(3) Interrupt enable DIP switches
(4) Auto-call DIP switches
(4) Auto-talk/listen DIP switches
(4) Talk latch disable DIP switches
(4) Line length DIP switches
Environmental
32 - 122o F (0 - 50o C)
Dimensions (MS-704/RM-704)
19 in. W x 3.5 in. H x 10.5 in. D
x
(483 mm
88 mm x 267 mm)
Weight
MS-704 10.86lbs. (4.94 kg)
RM-704 10.07lbs. (4.58kg)
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.
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
4-5
4-6
MS-704/RM-704 FOUR-CHANNEL MAIN/REMOTE STATIONS
VGC offers 24 x 7 customer
support if you have an
Extended Warranty or
Service Contract.
Return Material
Authorization (RMA)
numbers are required for all
returns.
LIMITED WARRANTY
Vitec Group Communications (VGC) warrants that at the time of purchase, the
equipment supplied complies with any specification in the order confirmation
when used under normal conditions, and is free from defects in workmanship
and materials during the warranty period.
During the warranty period VGC, or any service company authorized by VGC,
will in a commercially reasonable time remedy defects in materials, design, and
workmanship free of charge by repairing, or should VGC in its discretion deem it
necessary, replacing the product in accordance with this limited warranty. In no
event will VGC be responsible for incidental, consequential, or special loss or
damage, however caused.
WARRANTY PERIOD
The product may consist of several parts, each covered by a different warranty
period. The warranty periods are:
• Cables, accessories, components, and consumable items have a limited
warranty of 90 days.
Both warranty and
non-warranty repairs are
available.
• Headsets, handsets, microphones, and spare parts have a limited warranty of
one year.
• UHF wireless IFB products have a limited warranty of one year.
• UHF wireless intercom systems have a limited warranty of three years.
• All other Clear-Com and Drake brand systems and products, including
beltpacks, have a limited warranty of two years.
The warranty starts at the time of the product’s original purchase. The warranty
start date for contracts which include installation and commissioning will
commence from the earlier of date of the Site Acceptance Test or three months
from purchase.
TECHNICAL SUPPORT
To ensure complete and timely support to its customers, VGC’s User Support
Center is staffed by qualified technical personnel. Telephone and email technical
support is offered worldwide by the User Support Center.
The User Support Center is available to VGC’s customers during the full course
of their warranty period. Telephone support during the warranty period will be
offered at no charge between 09:00 and 17:00 according to the customer’s local
time zone.
In addition, for customers who purchase an Extended Warranty or Service
Contract, 24-hour customer support is offered immediately upon purchase of
WARRANTY
i
such agreement. For more information, contact your authorized dealer,
distributor, or sales representative.
Instructions for reaching VGC’s User Support Centers are given below.
Telephone for Europe, Middle East and Africa: +49 40 6688 4040
Telephone for the Americas and Asia: +1 510 337 6600
Email: vitec.support@AVC.de
Once the standard warranty period has expired, the User Support Center will
continue to provide telephone support if you have purchased an Extended
Warranty or Service Contract. In these cases, you will have access to telephone
support 24 hours per day, 7 days per week.
WARRANTY REPAIRS AND RETURNS
Before returning equipment for repair, contact a User Support Center to obtain a
Return Material Authorization (RMA). VGC representatives will give you
instructions and addresses for returning your equipment. You must ship the
equipment at your expense, and the support center will return the equipment at
VGC’s expense.
For out-of-box failures, use the following contact information:
Europe, Middle East and Africa
Tel: +44 1223 815000 Email: customerservicesEMEA@vitecgroup.com
North America, Canada, Mexico, Caribbean & US Military
Tel: +1 510 337 6600 Email: customerservicesUS@vitecgroup.com
Asia Pacific & South America
Tel: +1 510 337 6600 Email: customerservicesAPAC@vitecgroup.com
VGC has the right to inspect the equipment and/or installation or relevant
packaging.
NON-WARRANTY REPAIRS AND RETURNS
For items not under warranty, you must obtain an RMA by contacting the User
Support Center. VGC representatives will give you instructions and addresses for
returning your equipment.
You must pay all charges to have the equipment shipped to the support center
and returned to you, in addition to the costs of the repair.
EXTENDED WARRANTY
ii
If you purchase an Extended Warranty, you are also given access free of charge to
the User Support Center 24 hours a day, 7 days a week.
You can purchase an extended warranty at any time during the first two years of
ownership of the product. The purchase of an extended warranty extends to five
WARRANTY
years the warranty of any product offered with a standard two-year warranty.
The total warranty period will not extend beyond five years. Any purchase of an
extended warranty provides 24 x 7 customer support in addition to the warranty
immediately upon purchase of the warranty extension.
Note: VGC does not offer warranty extensions on UHF wireless intercom
systems, or on any product with a 1-year or 90-day warranty.
SERVICE CONTRACT
VGC also offers service contracts that provide 24 x 7 telephone support, advance
replacements, training, proactive maintenance, on-site visits, and no charge for
repair or replacement of equipment. For more information, contact your
authorized dealer, distributor, or sales representative.
LIABILITY
THE FOREGOING WARRANTY IS VGC'S SOLE AND EXCLUSIVE
WARRANTY. THE IMPLIED WARRANTY OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE AND ANY OTHER
REQUIRED IMPLIED WARRANTY SHALL EXPIRE AT THE END OF
THE WARRANTY PERIOD. THERE ARE NO OTHER WARRANTIES
(INCLUDING WITHOUT LIMITATION WARRANTIES FOR
CONSUMABLES AND OTHER SUPPLIES) OF ANY NATURE
WHATSOEVER, WHETHER ARISING IN CONTRACT, TORT,
NEGLIGENCE OF ANY DEGREE, STRICT LIABILITY OR OTHERWISE,
WITH RESPECT TO THE PRODUCTS OR ANY PART THEREOF
DELIVERED HEREUNDER, OR FOR ANY DAMAGES AND/OR LOSSES
(INCLUDING LOSS OF USE, REVENUE, AND/OR PROFITS). SOME
STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF
INCIDENTAL OR CONSEQUENTIAL DAMAGES OR THE
LIMITATION ON HOW LONG AN IMPLIED WARRANTY LASTS, SO
THE ABOVE LIMITATIONS MAY NOT APPLY TO YOU. IN ANY
EVENT, TO THE MAXIMUM EXTENT PERMITTED UNDER
APPLICABLE LAW, VGC'S LIABILITY TO CUSTOMER HEREUNDER
SHALL NOT UNDER ANY CIRCUMSTANCES EXCEED THE COST OF
REPAIRING OR REPLACING ANY PART(S) FOUND TO BE
DEFECTIVE WITHIN THE WARRANTY PERIOD AS AFORESAID.
This warranty does not cover any damage to a product resulting from cause other
than part defect and malfunction. The VGC warranty does not cover any defect,
malfunction, or failure caused beyond the control of VGC, including
unreasonable or negligent operation, abuse, accident, failure to follow
instructions in the manual, defective or improperly associated equipment,
attempts at modification and repair not approved by VGC, and shipping
damage. Products with their serial numbers removed or defaced are not covered
by this warranty.
This warranty does not include defects arising from installation (when not
performed by VGC), lightning, power outages and fluctuations, air conditioning
failure, improper integration with non-approved components, defects or failures
WARRANTY
iii
of customer furnished components resulting in damage to VGC provided
product.
This limited warranty is not transferable and cannot be enforced by anyone other
than the original consumer purchaser.
This warranty gives you specific legal rights and you may have other rights which
vary from country to country.
iv
WARRANTY
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