CLEAR-COM ENCORE
SB-704 MAIN STATION
INSTRUCTION MANUAL
SB-704 Main Station Instruction Manual
Part Number 810346Z Rev. 3
Legal Disclaimers
Copyright © 2013 HME Clear-Com Ltd.
All Rights Reserved
Clear-Com, the Clear-Com logo, and Clear-Com Concert are trademarks or registered trademarks of HM Electronics, Inc.
The software described in this document is furnished under a license agreement and may be used only in accordance with the
terms of the agreement.
The product described in this document is distributed under licenses restricting its use, copying, distribution, and decompilation/
reverse engineering. No part of this document may be reproduced in any form by any means without prior written authorization
of Clear-Com, an HME Company.
Clear-Com Offices are located in California, USA; Cambridge, UK; Montreal, Canada; and Beijing, China. Specific addresses
and contact information can be found on Clear-Com's corporate website:
www.clearcom.com
Clear-Com Contacts
Americas and Asia-Pacific Headquarters
California, United States
Tel: +1.510.337.6600
Email: CustomerServicesUS@clearcom.com
Europe, Middle East, and Africa Headquarters
Cambridge, United Kingdom
Tel: +44 1223 815000
Email: SalesSupportEMEA@clearcom.com
Canada Office
Quebec , Canada
Tel: +1 (450) 653-9669
China Office
Beijing Representative Office
Beijing, P.R.China
Tel: +8610 65811360 / 65815577
CONTENTS
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
The Clear-Com Concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Intercom Power Status Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Selecting Microphones and Enabling the Speaker. . . . . . . . . . . . . . . . 1-4
Listening to Intercom Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Talking on Intercom Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
The All-Talk Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Monitoring Main Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Sending and Receiving Call Signals . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Linking Intercom Channels Together. . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
The Announce Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Channel Assignments Using the Slide Switch Matrix . . . . . . . . . . . . . 1-6
Remote Mic Kill Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Short-Circuit and Overload Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Summary of Main Front-Panel Keys, Lights, and Controls. . . . . . . . . . 1-10
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Installation Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Intercom Line Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Line Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Using the Link Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Fail-Safe Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Intercom Cable Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Portable Installation Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Permanent Installation Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Ground Isolation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Physical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Description of Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Headset Connector (Front Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Panel Mic Connector (Front Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Intercom Line Connectors (Rear Panel). . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Program Input (Rear Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Announce Output (Rear Panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
IFB/HOT Mic (Rear Panel, 1/4-Inch Phone Jack) . . . . . . . . . . . . . . . . . . 2-8
External Speaker (Rear Panel, 1/4-Inch Phone Jack). . . . . . . . . . . . . . . . 2-8
SB-704 MAIN STATION
i
Accessory (Rear Panel, DB-15F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Auxiliary Program Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Remote Mic On/Off Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Announce Relay Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Internal Option Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
IFB Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Run/Test Mode Jumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Program Audio Feed to Announce Output Jumper . . . . . . . . . . . . . . . . 2-10
Power Source Selection for Switchable Intercom Lines . . . . . . . . . . . . 2-11
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
SB-704 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
TECHNICAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . 4-1
SB-704 Main Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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
SB-704 MAIN STATION
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. WARNING: To reduce the risk of fire or electric shock, do not expose
this product to rain or moisture.
SB-704 MAIN STATION
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.
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 SB-704 station meets all relevant CE, FCC, UL, 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
SB-704 MAIN STATION
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 SB-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.
SB-704 MAIN STATION
1-1
Clear-Com main stations, power supplies, and certain remote stations each
Off
B
C
D
A
Party
Line
12345678910
Headset
Null
Pgm
Listen
Channel B
Null
Pgm
Listen
ChannelA
Null
Pgm
Listen
Channel C
Null
Pgm
Listen
Channel D
BCDA
Line
Length
Program
Interrupt
BCD
Auto-Talk
/Listen
B
C
D
A
Talk Latch
Disable
B
C
D
A
HS
Lim
B
C
D
A
Auto-Call
Speaker
On
Off
Volume
Channel DChannel CChannel BChannel A
Talk
Listen
Call
Talk
Listen
Call
Talk
Listen
Call
Announce
AllTalk
Link On
Mic Select
Panel
Headset
Mic On
Panel Mic
On
(Off)
(Default)
Panel Mic
Gain
Sidetone
Adjust
CH. B
CH.A
CH. C
CH. D
Short
SB-704
Program
Level
Program
On/Off
BCDA
Long
(Short)
Remote
Mic Kill
4 Channel Switchboard
Main Station
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.
Figure 1-1: SB-704 Front Panel
DESCRIPTION
The SB-704 main station is a four-channel microprocessor-controlled station
intended to work with other Clear-Com party-line products. The SB-704 is
designed for applications in which a person needs to communicate with up to
four groups of people and be able to quickly assign a remote station to any of
the four channels.
The station features a ten-position slide switch matrix that allows assignment
of any of the ten intercom lines to any of the four intercom channels, to an
isolated separate party line, or to an off position.
The following is a list of features found in the SB-704 intercom station:
• MICROPROCESSOR CONTROL: Most aspects of station
operation are under microprocessor control.
• REMOVABLE ACCESS PANEL: A removable front panel allows
access to most controls and option DIP switches.
• INDIVIDUAL CHANNEL CONTROLS: Each channel has
individual talk, listen, and call push-buttons 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).
1-2
SB-704 MAIN STATION
• INTERNAL IFB (IFB - Interrupt Foldback of program feeds):
Program feed 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.
• ASSIGNMENT MATRIX: Up to ten stations or groups of stations
can be assigned to any one of the four intercom lines.
• LINK FUNCTION: The SB-704 has a link function that places all
four channels into a common party line at the single push of a 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: 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.
• EXTERNAL SPEAKER OUTPUT: The SB-704 does not have a
panel-mounted speaker; however, the speaker amplifier output is
made available on the rear panel.
• SPEAKER ON/OFF SWITCH: The speaker output 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.
SB-704 MAIN STATION
• POWER SUPPLY WITH SHORT CIRCUIT PROTECTION:
The SB-704 features redundant powering to remote stations by
1-3
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.
NORMAL OPERATION
Once installed and operational, the SB-704 is easy to operate. The following
sections describe normal operation of the unit, use of controls available under
the access panel, and abnormal operation of the power distribution system.
Normal operation of the SB-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 on 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
• Listening to intercom channels
• Monitoring main program
• Talking on intercom channels
• The all-talk function
• Sending and receiving call signals
• Linking intercom channels together
• The announce function
• Channel assignments using the slide switch matrix
Intercom Power Status Lights
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 SB-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.
1-4
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 quickly
SB-704 MAIN STATION
as ½ second, depending upon whether there was a single or multiple short or
overload. The other channels continue to operate normally. The SB-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 between the gooseneck mic and the headset mic, move the
microphone select switch to the appropriate position.
The mic on/off pushbutton toggles the microphone on and off. The mic button
lights blue when the mic 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).
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
SB-704 MAIN STATION
1-5
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 send 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
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.
Tal 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. Tal 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.
Channel Assignments Using the Slide Switch Matrix
The ten assignment switches let you assign the switchboard destinations
(#1 - #10 on the rear panel) to any of the four main intercom channels (A, B,
C, or D), an isolated off channel, or a separate common party line just for
these inputs.
When the switchboard destinations are assigned to the off position, they are
isolated from all other switchboard destinations and isolated from the four
main intercom channels. Stations on one of these lines can only talk to each
other. A call signal on one of these lines will be indicated by the amber LED
above the particular matrix switch. Pressing the all talk button on the station
will send the microphone to the channel in the off position.
1-6
When the switchboard destinations are assigned to the party-line position, all
destinations that are placed in the party-line position will be connected into a
common party line isolated from the rest of the station. Pressing the all talk
SB-704 MAIN STATION
button on the station will send the microphone to all channels in the party-line
position.
Remote Mic Kill Function
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
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 SB-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
switch, in their default positions (up). The Headset Audio Limiter 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 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.
SB-704 MAIN STATION
1-7
• 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.
• 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 greater 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 push-button 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 adjust the null control on a given channel:
1. Turn the 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.
1-8
SB-704 MAIN 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.
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
The SB-704 has switch-selectable intercom-line termination networks. If
more than one SB-704 (or any other Master Station) is installed on the same
intercom lines then all of the terminations in all of the stations except one
must be disabled.
Note: If the link function is to be used on an SB-704 and there is more than
one main station 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 SB-704 is shipped
from the factory with all four lines terminated.
SHORT-CIRCUIT 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 approximately 0.5 seconds,
the SB-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 short in that line. Follow that
SB-704 MAIN STATION
1-9
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.
SUMMARY OF MAIN FRONT-PANEL KEYS, LIGHTS, AND CONTROLS
Table 1 summarizes the meaning of various front-panel keys, lights, and
controls.
Function “On” State “Off” State Momentary or Latching
Microphone Key
(activates selected microphone,
either panel or headset)
Listen Key (press to listen to
a channel)
Talk /Power-On Key (press
to talk on a channel)
Call Key (press to send a call
signal on a channel)
Announce Key (press to send
microphone’s audio to
“announce” output, i.e. PA
system)
Blue Off Latching only (activates automatically
when other keys such as Talk,
Announce, All Talk are pressed)
Green Off Latching only (can be set to activate
automatically with “talk”)
Amber Blue (indicates that
the station is
receiving power,
but the “talk’
feature is off)
Red
(flashing)
when
receiving
or sending
call signal)
Amber Off Momentary only
Off Momentary only
Both
1-10
SB-704 MAIN STATION
Function (Continued) “On” State “Off” State Momentary or Latching
All-Talk Key (press to send
microphone’s audio to all
channels)
Link-On Key (press to link all
channels together so that station
operates as one party line)
Remote Microphone Kill Key
(press to clear all latched talks
on connected remote
stations/beltpacks on all
channels)
Short/Overload Light (lights
when there is a short or overload
on the associated channel)
Mic Select Switch (to select to
activate either the panel or
headset microphone)
Speaker On/Off Switch (to
switch station speaker on or off)
Volume Knob (adjusts overall
incoming volume on all
channels)
Amber Off Momentary only
Amber Off Latching only
Amber Off Momentary only
Red Off Neither
n/a n/a n/a
n/a n/a n/a
n/a n/a n/a
Listen Level Knob (adjusts
incoming volume to selected
channel only)
Channel Slide Switch (assigns
each of 10 individual stations to
one of four channels)
Channel Light (shows if there is
a call signal on a channel)
n/a n/a n/a
n/a n/a n/a
amber off n/a
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.
SB-704 MAIN STATION
1-11
1-12
SB-704 MAIN STATION
INSTALLATION
This chapter describes installation of the SB-704 in an intercom system.
INSTALLATION OVERVIEW
This section describes the Clear-Com concept in intercom line
interconnection under the following topics:
• Intercom Line Connection
• Line Termination
• Station Powering
• Cable Considerations
INTERCOM LINE CONNECTION
The SB-704 provides one male XLR-3 connector for each main intercom line
and ten male XLR-3 connectors for the separate assignable intercom
channels.
LINE TERMINATION
The fundamental concept of the Clear-Com party-line intercom is that all
stations provide high impedance into a single system termination.
Note: 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 SB-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 imbalance of hybrid null circuits.
Switching of the termination on and off on the SB-704 is with back-panel
switches. The SB-704 is shipped from the factory with all four lines
terminated.
USING THE LINK FUNCTION
The link function in the SB-704 uses relays to connect 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
SB-704 MAIN STATION
2-1
link is activated. If there is more than one SB-704 or MS-704 in a system, the
1
2
3
4
5
67
8
9
10
11
121314 15
16
17
18
19
20
5
10
15
20
0
0
0.5
2
4
7
14
20
Number of
seconds to
restore
Number of recent shorts or overloads
link function can only be used at the station where the terminations are set on.
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 SB-704’s power supply:
• AUTOMATIC SHORT CIRCUIT PROTECTION: The SB-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 SB-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 SB-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:
2-2
Figure 2-2: Automatic Power Restore Times
SB-704 MAIN STATION
• 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 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 SB-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.
• LOW NOISE CIRCUITRY: The direct current outputs of the SB-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 SB-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.
SB-704 MAIN STATION
2-3
SB-704
RM-704
Remote
Station
Figure 2-3: Fail Safe Power Distribution
The illustration above shows the proper power wiring of a system powered by
a single SB-704. The single-channel remote stations are connected to the ten
switched intercom connectors. These connectors derive their DC power
internally from the SB-704. The station comes set from the factory with the
power on the assigned lines #1 - #5 connected to channel A's power. The
power for channels #6 - #10 is sourced from channel B. Multiple-channel
remote stations are connected to the four intercom channels. In the case
above, a short on any one line will only take that channel down.
2-4
It is assumed that none of the power lines are interconnected in the external
system wiring. However, if a multiple-channel remote station that has not
been equipped for power line isolation is connected, those channels would
now have their power lines connected. The system will still work except that a
short circuit on any of the interconnected channels will cause both to fail thus
taking more of the system down with a single short circuit.
INTERCOM CABLE CONSIDERATIONS
The Clear-Com intercom line is intended to run on 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.
SB-704 MAIN STATION
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.
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.
SB-704 MAIN STATION
2-5
Figure 2-4: 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.
2-6
SB-704 MAIN STATION
AUX
On
Off
On
Off
On
Off
ELECTRICSHOCKDO NOT
FIREORSHOCK HAZARD DO NOT
EXPOSETHISEQUIPMENT TO RAIN
TO
P
R
E
V
E
N
T
TOPREVENT
WARNING:
ORMOISTURE.
CAUTION:
REMOVECOVER.NO USER
SERVICEABLEPARTSINSIDE.
REFERTOQUALIFIED SERVICE
PERSONNEL.
SB-704
HOTMIC/IFB
EXTERNAL
SPEAKER
CHANNELA
CHANNELC
CHANNELB
CHANNELD
5
109
1234
PROGRAMIN
ANNOUNCEOUT
RM-704
HOTMIC/IFB
CHANNELA
CHANNELC CHANNELD
CHANNELB
PROGRAMIN
ANNOUNCEOUT
AUX
RM-704
SB-704
1-Channel Beltpacks
utput:30V, 1.2A Continuous, 2A Pe
ss2 Wiring
Figure 2-5: Typical Mixed System Wiring
PHYSICAL INSTALLATION
You can install the SB-704 in a standard equipment rack, or you can use it as
stand-alone unit sitting on a table or desk. For installing in an equipment rack,
the unit requires 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
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
Note: Do not tie pin #1 and pin #3 together.
SB-704 MAIN STATION
PANEL MIC CONNECTOR (FRONT PANEL)
Two plug-in panel microphones are available for use on the SB-704. The
GM-9 is 9 in. (23.04 cm) long and GM-18 is 18 in. (46.08 cm) long. The
microphone is of the electret type. The microphone has a built-in 0.25-in.
2-7
(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:
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 SB-704 has a single male XLR-3 connector for each intercom line. The
ten switched intercom lines also have male XLR-3 connectors. 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 and 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
ANNOUNCE OUTPUT (REAR PANEL)
A 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)
2-8
SB-704 MAIN STATION
Pin 2 --- - Signal
Pin 3 --- + Signal
The signal level is 0 dBu and transformer isolated.
IFB/HOT MIC (REAR PANEL, 1/4-INCH PHONE JACK)
A ¼ 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
EXTERNAL SPEAKER (REAR PANEL, 1/4-INCH PHONE JACK)
A ¼ in. (0.64 cm) phone jack marked external speaker provides the power
amplifier output of the station intended for driving an external speaker. The
jack connections are as follows:
Tip --- Speaker amplifier output
Ring --- No connection
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:
SB-704 MAIN STATION
2-9
Figure 2-6: Accessory Connector DB-15F - Rear View
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 which
is active if the function has been activated with an option DIP switch and a
talk is active on that channel.
Refer to the illustration 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 amps of DC current at 24 VDC and are electrically isolated from the
rest of the station.
2-10
SB-704 MAIN STATION
INTERNAL OPTION JUMPERS
There are several jumper options inside the chassis of the SB-704. To access
these options remove the top cover of the unit.
Note: Remove AC power from the unit before removing the top cover.
Note: This adjustment should only be carried out by qualified service
personnel.
The following options are available:
• IFB Operation Mode Select
• Run/Test Mode Jumper
• Power source selection for switchable intercom lines
• Program Audio Feed to Announce Output
IFB MODE
The SB-704 supports 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 jumper 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 SB-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
SB-704 MAIN STATION
2-11
announce output and replaces it with audio from the selected panel or headset
A B C D
CH 1-5
CH 6-10
POWER DIST.
SOLDER THESE
JUMPERS
CUT THESE
TRACES
microphone.
The factory default position for J11 is in the off position, blocking program
audio feed from the announce output.
POWER SOURCE SELECTION FOR SWITCHABLE INTERCOM LINES
The power pins (pin #2) of the ten switchable intercom connectors are
connected together in two groups of five. Internal jumpers on the rear-panel
PCB board allow the selection of the source of power for each of these
groups. Either of the groups can be powered from channels A, B, C, or D's
power feed to the main intercom lines.
As shipped from the factory, the first five (channels #1 - #5) are powered from
channel A's power and the second five (channels #6 - #10) are powered from
channel B’s power.
A jumper field in the middle upper portion of the rear panel printed wiring
board has been provided for changing the power source of the switchable
intercom lines.
To change the factory default setting, refer to the illustration below.
2-12
If the first bank (channels #1 - #5) are to be changed, cut the PCB trace
(between the top pad marked A and the center pad just below it) with a knife
or scraping tool, then solder a wire jumper between one of the top pads
marked A, B, C, or D to the pad just below it (depending on which channel the
power is to come from).
If the second bank (channels #6 - #10) are to be changed, cut the PCB trace
(between the bottom pad marked B and the center pad just above it) with a
knife or scraping tool, then solder a wire jumper between one of the bottom
pads marked A, B, C, or D to the pad just above it (depending on which
channel the power is to come from).
Figure 2-7: Jumper Fields
SB-704 MAIN STATION
SB-704 MAIN STATION
2-13
2-14
SB-704 MAIN STATION
MAINTENANCE
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.
SB-704 BLOCK DIAGRAM
SB-704 MAIN STATION
3-1
Figure 3-8: SB-704 Block Diagram
3-2
SB-704 MAIN STATION
TECHNICAL SPECIFICATIONS
SB-704 MAIN STATION
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 >= 15dB
Headset Microphone Input
Input Type Dynamic
Input Impedance >= 1K
Mic Limiter Threshold 0dBu ± 3dB
Mic Limiter Range >= 15dB
Ω
Ω
Program Line Input
Maximum Level before Clipping >= 20dBu
Input Impedance >= 5K
Ω
Headset Output
Load Impedance >= 8
Output Impedance <= 25
Output Limiter Threshold +5dBu ± 3dB
Maximum Output Level before Distortion >= 17dBu
Ω
Ω
Speaker Output
Load Impedance >= 4
Max Output Level before 1% Distortion 20dBu ± 2dBu
Ω
Party Line Output
Off Noise < -74dBu
Output Impedance >10K
Ω
Party Line Input
Crosstalk < -60dB
Max level before Clipping >= 12dBu
Sidetone Null Capability > 25dB
SB-704 MAIN STATION
Stage Announce/Balanced Line Out
Type Balanced
4-1
Output Impedance >= 200
Load Impedance >= 600
Ω
Ω
IFB/Hot Mic
Type Unbalanced
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
4-2
SB-704 MAIN STATION
Min Gain
Panel Mic - Party Line <= 25dB
Mains Power
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
Up to 40 1-Channel Beltpacks, 10
speaker stations or 12 headset
stations distributed over all
channels
Rear Panel Connectors
Switched Intercom: (10) XLR-3M (1 per channel)
Intercom (4) XLR-3M (1 per channel)
Announce Out: (1) XLR-3M (audio)
Program: In (1) XLR-3F
Hot Mic / IFB Interface: (1) 1/4 in. (0.64 cm) phone jack
External Speaker (1) 1/4 in. (0.64 cm) phone jack
Accessory (1) DB-15F
AC Power: IEC 320 connector
SB-704 MAIN STATION
Rear Panel Controls
(1) Power switch
(4) Intercom On/Off Switches
Front Panel Connectors
Panel Mic: (1) 1/4 in. (0.64 cm) panel
mounting jack
Headset: (1) XLR-4M
Front Panel Controls & Indicators
(1) Panel / headset mic switch
(1) Mic on button
(1) All talk button
(1) Announce button
(1) Party line link button
(4) Program
ON-OFF-INTERRUPT
DIP switches
(1) Program level control
4-3
(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
(10) Channel Assignment Slide
switches
Environmental
32 - 122o F (0 - 50o C)
Dimensions
19 in. W x 3.5 in. H x 10.5 in. D
(483 mm
x
88 mm x 267 mm)
Wei ght
10.93 lbs. (4.97 kg)
Notice About Specifications
While Clear-Com makes every attempt to maintain the accuracy of the
information contained in its product manuals, that information is subject to
change without notice. Performance specifications included in this manual
are design-center specifications and are included for customer guidance and
to facilitate system installation. Actual operating performance may vary.
4-4
SB-704 MAIN STATION
Clear-Com 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
Clear-Com 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 Clear-Com, or any service company authorized by
Clear-Com, will in a commercially reasonable time remedy defects in
materials, design, and workmanship free of charge by repairing, or should
Clear-Com in its discretion deem it necessary, replacing the product in
accordance with this limited warranty. In no event will Clear-Com 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:
Both warranty and
non-warranty repairs are
available.
• Cables, accessories, components, and consumable items have a limited
warranty of 90 days.
• 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, Clear-Com’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 Clear-Com’s customers during the
full course of their warranty period. Telephone support during the warranty
WARRANTY
i
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
such agreement. For more information, contact your authorized dealer,
distributor, or sales representative.
Instructions for reaching Clear-Com’s User Support Centers are given below.
Americas and Asia-Pacific Headquarters California, United States Tel:
+1.510.337.6600 Email: CustomerServicesUS@clearcom.com
Europe, Middle East, and Africa Headquarters Cambridge, United
Kingdom Tel: +44 1223 815000 Email: SalesSupportEMEA@clearcom.com
Canada Office Quebec, Canada Tel: +1 (450) 653-9669
China Office Beijing Representative Office Beijing, P.R.China Tel: +8610
65811360 / 65815577
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). Clear-Com 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 Clear-Com’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
ii
Clear-Com has the right to inspect the equipment and/or installation or
relevant packaging.
WARRANTY
NON-WARRANTY REPAIRS AND RETURNS
For items not under warranty, you must obtain an RMA by contacting the
User Support Center. Clear-Com 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
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 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: Clear-Com does not offer warranty extensions on UHF wireless
intercom systems, or on any product with a 1-year or 90-day warranty.
SERVICE CONTRACT
Clear-Com 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 CLEAR-COM'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
WARRANTY
iii
EVENT, TO THE MAXIMUM EXTENT PERMITTED UNDER
APPLICABLE LAW, CLEAR-COM'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 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 improperly
associated equipment, attempts at modification and repair not approved by
Clear-Com, 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 Clear-Com), lightning, power outages and fluctuations, air
conditioning failure, improper integration with non-approved components,
defects or failures of customer furnished components resulting in damage to
Clear-Com 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
Loading...