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Rev. 5 – 12/07
ENVOY SYSTEM
Operation Manual
The following declaration is applicable to equipment bearing the CE
mark, manufactured for use in European Union and affiliated countries.
It does not necessarily apply to non-CE marked equipment (although in
many cases this will be manufactured to identical specifications).
DECLARATION OF CONFORMITY
The following declaration is made in application of Council directives:
73/23/EEC (Low Voltage Directive)
89/336/EEC (Electromagnetic Compatibility)
It is hereby warranted that the equipment described below complies with the
requirements of the European standards:
EN 60065:1993 (Electrical Safety)
EN 50081-1:1992 (EMC - Emissions)
EN 50082-1:1992 (EMC - Immunity)
Type of Equipment: Conference Equipment
Model Numbers: DSC50, DSC100, APU100E
DDU/CDU Series Discussion Units
DIU6 Interface Unit
I, the undersigned, hereby declare that the equipment described herein
conforms to the above Directives and Standards.
Envoy System Operation Manual ii
Full Name: Graham P. Booth, B. Eng
Position: Technical Director
D
ate: December 2007
CONTENTS
SECTION TITLE PAGE
1.0 INTRODUCTION 1-1
2.0 DSC DISCUSSION SYSTEM CONTROLLERS 2-1
2.1 Introduction 2-1
2.2 Before Use 2-2
2.3 Controls And Facilities 2-2
3.0 DELEGATE & CHAIRMAN UNITS 3-1
3.1 Controls And Facilities 3-1
4.0 OPERATING INSTRUCTIONS 4-1
4.1 DSC Network Controller 4-1
4.2 Delegate Units 4-4
4.3 Chairman Unit 4-6
5.0 INSTALLATION 5-1
5.1 DSC Network Controller 5-1
5.2 Delegate Units 5-6
5.3 Commissioning Procedures 5-8
6.0 CONFIGURATION & SETTING UP 6-1
6.1 DIL Switch Settings 6-1
6.2 Menu Options 6-2
6.3 Feedback Suppression 6-6
7.0 TECHNICAL DATA 7-1
7.1 Microphone Units 7-1
7.2 DSC50 Network Controller & Power Supply Unit 7-2
8.0 MAINTENANCE 8-1
8.1 Cleaning 8-1
8.2 Fuses 8-1
8.3 General 8-2
9.0 APU AUXILIARY POWER SUPPLY UNITS 9-1
9.1 Introduction 9-1
9.2 Controls & Facilities 9-1
9.3 Installation 9-2
9.4 Operation 9-2
Envoy System Operation Manual iii
10.0 DIU6 INTERFACE UNIT 10-1
10.1 Introduction 10-1
10.2 Controls & Facilities 10-1
10.3 Installation 10-2
10.4 Configuration 10-2
10.5 Operation 10-3
A1.0 FIXED DELEGATE UNIT INSTALLATION CABLING A1-1
A2.0 AUDIO INTERFACING A2-1
A2.1 Balanced Or Single-Ended? A2-1
A2.2 Output Configurations A2-1
A2.3 Input Configurations A2-3
A2.4 Interconnections A2-4
A3.0 SYSTEM CONTROL INTERFACE A3-1
A3.1 SCI Output Message Format A3-1
A3.2 SCI Input Command Format A3-3
A3.3 Enabling The SCI A3-5
A3.4 Serial Interface A3-6
___________________
USER NOTES:
Envoy System Operation Manual iv
1.0 INTRODUCTION
Envoy System Operation Manual 1-1
This manual describes the operation and installation of the Envoy series of
discussion units, and their associated Discussion System Controllers – the DSC50 &
DSC100 (hereafter just referred to as DSC).
The Envoy system is designed to fill the need for a simple, compact discussion system
providing good audio performance at an attractive price. The Envoy delegate units go
beyond this however, by providing features normally only found on professional
conference systems costing much more, e.g.
x High quality cardioid electret microphone with high visibility ring luminant – as used
on the IDN system.
x Full range loudspeaker
x Delegate or Central control of microphones (latter with addition of PC or Manual
Switching Unit).
x Self-Cancelling operating mode.
x Parliamentary (3-way) voting as standard (in conjunction with PC).
x “Soft” addressing – no switches to set.
x Chairman unit with Priority facility.
The central DSC unit also has a wealth of features, including:
x Configuration setup from the front panel via easy to use menu navigation system
in conjunction with backlit Liquid Crystal text display. No internal jumpers to set.
x Built in monitoring loudspeaker.
x Serial control port provided as standard (for connection of PC or Manual Switching
Unit).
x Balanced (XLR) Auxiliary Input with presettable gain to cater for signals from mic
to line level.
x Balanced (XLR) Line Level Floor output to Interpretation, AFILS etc.
x Balanced (XLR) Line Level PA output to PA amplifiers.
x Balanced (XLR) Loudspeaker Input – allows external loudspeaker signal
processing.
x Unbalanced (DIN) Tape In/Out connector with menu Record/Play selection.
x Tri-colour LED audio level indicators for Auxiliary Input, PA and Output channels.
x Frequency shifter module option for feedback reduction.
Although intended for relatively small applications, Envoy can be expanded up to 256
units with the addition of Auxiliary Power Supply Units.
The Envoy system uses the latest microprocessor technology to ensure simple, rapid
and flexible operation with the highest levels of reliability and quality. It allows the
system cabling to be reduced to just seven conductors with no active floor splitter boxes
or multi-conductor trunk cables being necessary.
Blank Page
2.0 DSC DISCUSSION SYSTEM CONTROLLERS
Envoy System Operation Manual 2-1
2.1 INTRODUCTION
The DSC is the hub of the Envoy system, providing the power for the delegate units and
also incorporating control and audio processing electronics. A DSC can support up to
256 delegate units, but only supplies power for around 50 (DSC50), or 100 (DSC100)
units. Additional power can be provided by APU auxiliary power supply units.
The DSC is versatile enough to satisfy the demands of most technicians, yet
straightforward to use and unintimidating for non-technical personnel.
2.1.1 Summary of Features
There follows a brief summary of features. These will be explained in greater detail in
subsequent sections of this manual.
PHYSICAL:
x Compact 2U high steel chassis. 19" rack mountable
x Fully enclosed with ventilated lid
x Case option for portable/desktop use.
POWER SUPPLY SECTION:
x Capacity – 50 (DSC50) or 100 (DSC100) Envoy delegate/chairman units
x Protection – Overload and short circuit proof. Over-temperature shutdown.
x Fault alert via front panel information display panel and LED indicator
AUDIO INPUTS:
x Auxiliary Input 1 – Balanced input via XLR connector. Selectable sensitivity
(-60/-40/-20/0dBu) and Phantom Power option. Priority gating option, front panel
rotary signal level control and indicator.
x Loudspeaker Input – Balanced, line level (0dBu) input via XLR connector.
AUDIO OUTPUTS:
x Auxiliary Output – Electronically balanced output via 3-pin XLR connector. Fixed
level (0dBu) with level indicator.
x PA Output – Electronically balanced output via 3-pin XLR connector. Output at
nominal line level (0dBu), variable via front panel rotary control. Signal level
indicator. Optional auxiliary processing (Frequency Shifter) module.
TAPE INPUT/OUTPUT:
x 2 channel single-ended inputs and outputs – suitable for use with stereo tape
recorders. Via 5-pin DIN connector on rear panel.
x Nominal input/output level –0dBu (fixed).
x Record/Play switching via front panel menu system. Avoids plug swapping.
MONITORING FACILITIES:
x Monitor loudspeaker incorporated in front panel.
x Monitor level adjusted via front panel rotary control.
DSC Discussion System Controllers
Envoy System Operation Manual 2-2
CONTROL FACILITIES:
x Alert LED for immediate warning of change in operating status.
x Background diagnostic function – continuously scans delegate units connected to
the system and displays number found.
x Menu options accessed via front panel LCD information display and pushbutton
switches, with prompt LED indicators:
- Operating Mode (Central/delegate etc.)
- Live Microphone Limit
- Tape Record/Playback selection
- Address Setup
- Gain Setting Mode
- Auto-Off Mode
- Control Functions (Cancel Mics, Clear Requests etc.)
- Auxiliary Processing Module (Enable/Disable)
x Settings are stored in non-volatile memory (EEPROM) and are retained indefinitely
when the power is removed.
INTERFACE:
x Serial Input/Output. For connection to Conference Control Unit(s).
2.2 BEFORE USE
1. Read the instructions contained in this, and other manuals pertaining to the
system, carefully. It is particularly important when using the equipment for the first
time that the guidelines given in the Installation section of this manual have been
followed. Failure to observe these could result in damage to the equipment.
2. Ensure that the DSC is positioned such that it is adequately ventilated. Do not
allow the airflow around the unit to be impeded - e.g. by covering the ventilation
grilles, by placing on a soft surface such as piled carpet or by installing in an
enclosed cabinet.
2.3 CONTROLS AND FACILITIES
2.3.1 Front Panel
13 5 7 8 10 11
p p p p p p p
n n n n n
24 6 9 12
Fig. 2.1 – DSC Front Panel
DSC Discussion System Controllers
Envoy System Operation Manual 2-3
1. AUXILIARY INPUT LEVEL INDICATOR – Tri-colour LED lamp which gives a
visual indication of the signal level on this input channel.
2. AUXILIARY INPUT LEVEL CONTROL – Rotary control with click stop “off”
position. Varies the amount of signal passed through from this input channel.
3. PA CHANNEL LEVEL INDICATOR – Tri-colour LED lamp which gives a visual
indication of the signal level on the PA (output) channel.
4. PA CHANNEL LEVEL CONTROL – Rotary control with click stop “off” position.
Varies the amount of floor channel signal passed through to the PA channel.
5. ALPHANUMERIC STATUS DISPLAY (LCD) – Liquid Crystal Display panel that
gives information about the current system status, and is used during setting up
the operating parameters.
6. ALERT INDICATOR – Bi-Colour LED indicator which illuminates red or green to
show the current system integrity.
7. MENU BUTTONS – Five push button switches, used to navigate the menu system
to set various operating parameters.
8. OUTPUT LEVEL INDICATOR – Tri-colour LED lamp which gives a visual
indication of the output signal level
9. MONITOR LOUDSPEAKER LEVEL CONTROL – Adjusts the sound level from
the front panel loudspeaker.
10. MONITOR LOUDSPEAKER – Enables the output signal to be audibly monitored.
11. MAINS POWER INDICATOR – Green LED indicator - illuminates when the unit is
switched on.
12. MAINS POWER SWITCH – Two position rocker switch used to apply power to the
system.
2.3.2 Rear Panel
13
p p
n n n n n n n n
245678910
Fig. 2.2 – DSC Rear Panel
1. MAINS SUPPLY VOLTAGE SELECTOR - Two position slide switch selects either
115V or 230VAC nominal supply voltage.
2. MAINS SUPPLY INPUT SOCKET/FUSE HOLDER - IEC320 type.
3. DELEGATE ZONES - Four off 7-pin latching DIN sockets. The delegate unit
strings are connected via these sockets.
DSC Discussion System Controllers
Envoy System Operation Manual 2-4
4. SERIAL I/O – 9-way "D-type" socket. Provides a serial data link between the DSC
and central control units.
5. PA OUTPUT - 3-pin XLR male socket. Line level output suitable for feeding
additional sound reinforcement equipment.
6. AUXILIARY OUTPUT - 3-pin XLR male socket. The output from the microphone
system is available on this connector at line level for feeding to other equipment -
Sound Reinforcement, Interpretation, Broadcast, Recording etc.
7. TAPE RECORDER CONNECTOR 5-pin 180q DIN connector, via which a standard
stereo tape deck may be connected for record/playback.
8. LOUDSPEAKER INPUT - 3-pin XLR female socket. Accepts a line level signal
which drives the loudspeakers in the delegate units.
9. AUXILIARY INPUT - 3-pin XLR female socket. Accepts signals from external
equipment, hand held microphones etc.
10. DIL SWITCHES – An array of 8 individual mini-switches that configure various
operating parameters.
3.0 DELEGATE & CHAIRMAN UNITS
Envoy System Operation Manual 3-1
Envoy was conceived as a simple, straightforward system without the multitude of
variants that are available in the IDN series for example. There are just four main
variants:
Portable Delegate Unit – DDU103P
Flush Mounting Delegate Unit – DDU103F
Portable Chairman Unit – CDU103P
Flush Mounting Chairman Unit – CDU103F
Portable units are housed in a free standing impact resistant moulded ABS enclosure
(see Fig. 3.1). The microphone is a composite stem type with flexible section, which
allows it to be folded down for storage. The microphone head incorporates a high visibility
ring luminant. Cables and connectors are integral to the units, allowing them to be quickly
and easily plugged together.
Flush mounting versions are intended to be permanently installed in the furniture. They
are mounted on a painted steel or anodised aluminium panel, which can be recessed into
a cut-out in the desk or table top. A protective metal back box is normally supplied. The
microphone is the same type as the portable unit, with composite stem and ring luminant.
The units incorporate screw terminal blocks for connection to the installation cabling.
3.1 CONTROLS & FACILITIES
The example drawing below depicts a standard DDU103P portable delegate unit.
1
3
4
5
2
6
Fig. 3.1 – DDU103P
Delegate & Chairman Units
Envoy System Operation Manual 3-2
1. CONTINUATION CONNECTOR – Socket into which the next unit in the chain can
be connected.
2. INPUT CABLE – Fitted with 7-pin latching DIN plug. Connects to previous unit in
chain (or DSC zone outlet).
3. MICROPHONE - Picks up sound when the unit is "live". Composite stem semi-rigid
type with ring luminant.
4. LOUDSPEAKER - Provides local sound reinforcement.
5. VOTING SWITCHES & INDICATORS - Three pushbutton switches with integral red
LED indicators. These are labelled + (for), 0 (abstain) and - (against).
6. REQUEST SWITCH - Pushbutton switch with integral bi-colour LED indicator. In
Delegate Mode, this allows the user to turn their microphone on and off directly. In
Central Mode, it is used to signal the operator that the delegate wishes to take the
floor (and also to temporarily inhibit the microphone when the unit is "live"). The
indicator illuminates Green to confirm that the delegate's request has been lodged at
the Central Control Unit and red to confirm that the microphone is enabled.
The only visible difference between Delegate and Chairman units is that on the latter,
the “REQUEST” switch is coloured yellow. In fact, the chairman does not make
requests, and this is actually a MIC/PRIORITY button.
4.0 OPERATING INSTRUCTIONS
Envoy System Operation Manual 4-1
This section describes how the equipment is used. It is assumed that the system has
been set up in accordance with the instructions given in the Installation section of this
manual. Reference should also be made to the Operation Manuals for any central control
unit that may be connected to the system.
In the text which follows, an asterisk (*) is used to indicate that further information on the
subject may be found in the Installation section of this manual.
4.1 DSC NETWORK CONTROLLER
4.1.1 Mains On/Off
Mains power to the DSC is controlled by the front panel Power switch. When the DSC is
turned on, DC power is applied to the delegate system (delegate and chairman units).
The associated green indicator illuminates to confirm this. In a minimum system, the
DSC may be the only item of mains powered equipment. In larger systems, the control
equipment should be powered up in the following order:
x APU Auxiliary Power Supply Unit(s)
x DSC50/100
x CPM301/2, CPM401/2 etc. Manual Switching Unit(s)
x Audio Equipment (amplifiers, line splitters etc.)
x Computer & associated equipment
The system may have been installed such that the power to the equipment rack is
switched by a single breaker.
When first powered up, a sign-on message will be initially displayed on the DSC’s LCD
information panel. The Alert LED will also begin to flash – normally green, but
sometimes red. The LCD panel will then show the following message:
Scanning Network
Please wait..
During this period the unit interrogates every possible unit which may be connected to
the system. The total number of units found is calculated, and after a few seconds a
message of the following type is normally displayed:
Mode: Central
Units found: 123
This is the default display for the unit. Something other than “Central” may be displayed
for the mode, and the number of units reported will obviously vary according to the
system.
Operating Instructions
Envoy System Operation Manual 4-2
It is good practice to ensure that the number of units reported at this point is as
expected. If not, the number reported will usually be less than expected. Possible
reasons for this are:
x Some units are not connected, or not properly connected.
x There are some units with duplicate address settings.
x Auxiliary power supplies not activated.
4.1.2 Operating Mode
There are two basic operating modes for the system - Central and Delegate. The
current operating mode can also be changed from the DSC front panel*, or from a
Conference Control Unit (e.g. CPM401 Manual Switching Unit, or a Conference Control
Computer) if connected.
Important - The system is reset (all microphones and requests will be cancelled) when
the operating mode is changed.
DELEGATE MODE
This is the normal operating mode for a discussion system. It is sometimes also referred
to as "Automatic" or "Emergency" mode. Basic microphone operation is possible with
delegates turning their own microphones on and off. Delegate Mode must be selected if
there is no central control equipment connected.
When operating in Delegate Mode it is sensible to restrict the number of microphones
permitted to be live to just two or three. There are two variants of Delegate Mode, which
differ in respect of what happens once this pre-set limit has been reached.
In Delegate/Block mode, once the pre-set number of live microphones has been
reached, subsequent requests from delegates will be rejected and they are therefore
blocked.
In Delegate/FIFO mode, once the pre-set number of live microphones has been reached,
subsequent requests are queued. As the live microphones are turned off, the requesting
delegates are enabled on a First-In, First-Out basis. The number of live microphones is
maintained at the pre-set limit while there are delegates in the request queue waiting to
speak. Note that in this mode, a Cancel Mics operation will also clear any requests
pending.
The Delegate Mode variant and the permitted number of live microphones is set via the
DSC’s menu selection facility*.
CENTRAL MODE
In this mode, delegates generally have no direct control over their microphones - they can
only signal a request to speak to the operator at the control unit. The control console will
normally select Central Mode when powered up. Do not select this mode if there is no
Central Control Unit connected.
4.1.3 Auxiliary Input
If the auxiliary input channel is used, the corresponding rotary control on the front panel
should be adjusted to achieve the required signal mix. The tri-colour indicator LED
illuminates with varying intensity and colour according to the signal level through the
Operating Instructions
Envoy System Operation Manual 4-3
channel. At low and normal signal levels it is green, progressing through amber and
then red as the signal increases. If the LED illuminates predominantly red, it is indicative
that the input signal is at too high a level and is likely to overload the Auxiliary Input pre-
amplifier. The input signal should be reduced, or the pre-amplifier gain altered*. The
rotary control does not vary the pre-amplifier gain – merely the amount of signal
contribution from this channel to the overall floor language.
If the Auxiliary Input channel is not in use, the rotary control should be turned fully anti-
clockwise, past the click stop. Otherwise, excess noise may be generated from an
open-circuit input.
4.1.4 PA Channel Control
This rotary control (marked by a loudspeaker symbol) adjusts the signal level through the
DSC’s PA channel. Usually (but not necessarily), this will control the sound level produced
by the loudspeakers in the microphone units (if fitted), and any external PA system. This
control will usually be left at a predetermined optimum setting for the particular application.
If turned too low, the sound from the loudspeakers will be inadequate. If it is set too high,
the sound level will be sufficient to cause acoustic feedback (howlround). As with the
Auxiliary Input channel, a tri-colour LED shows the signal level through the PA channel.
Note that in systems incorporating other items of audio processing equipment (line
splitters, graphic equalisers, sound control consoles etc.), there may be more than one
control affecting the loudspeaker levels. In these more complex cases it is advisable that
alteration of settings only be carried out under the guidance of the AV technician
responsible for the equipment.
4.1.5 Monitoring
The rotary control in the Monitoring section adjusts the sound level produced by the
integral loudspeaker.
The tri-colour LED in the Monitoring section gives an indication of output signal level
(from the Auxiliary Output). The output signal is not affected by the rotary control.
4.1.6 Error Reports
The DSC is capable of detecting several error conditions. These will be reported to the
operator via the front panel information display, attention being drawn by Alert LED
flashing red.
Some errors are transient and the error display will clear after a few seconds. An
example of this is when a CCU is brought on/off line (e.g. switching off a Manual
Switching Unit) while the DSC is running. An error of the following type will be
displayed:
SYSTEM ERROR
SIO1 comms fail
More serious errors remain displayed until the operator acknowledges by pressing the
front panel OK menu button. An example of this is:
MEMORY C/S ERROR
Parameters reset
Operating Instructions
Envoy System Operation Manual 4-4
This might occur at power up, and is a warning that the parameters stored in EEPROM
have not been retrieved correctly (checksum error detected), and have therefore been
reset*. Pressing the OK menu button will clear this message. It is highly unlikely that this
message will ever be seen.
Another error that must be cleared by the operator is a power supply overload fault (see
Installation section).
4.2 DELEGATE UNITS
4.2.1 Microphone Operation In Delegate Mode
When the system is running in Delegate Mode, delegates control their own microphones.
A person wishing to speak presses their REQUEST button, whereupon the microphone
will normally become "live" immediately. Pressing the button a second time switches the
microphone off again. The "cough" facility (see below) is not available when operating in
this mode.
The number of microphones permitted to be live at any time is pre-set*. The system can
be programmed* to either block requests once this limit has been reached, or to store the
requests in a queue. As microphones are turned off, the queue is advanced, and
requesting units are enabled on a First-In, First-Out (FIFO) basis.
If there is no operator, it is important for the delegates to remember to switch their
microphones off when they have finished speaking, otherwise the effectiveness of the
system will be diminished and eventually new speakers will be prevented from coming on.
If a central control unit is connected and there is someone to monitor the system status -
albeit on a part time basis - it is still possible for them to intervene if necessary.
As in Central Mode, if the chairman's priority function is engaged all microphones are
inhibited. If there is no central control unit "on-line" (i.e. a DSC-only system), those
microphones cancelled will not be restored again when priority is released.
4.2.2 Microphone Operation In Central Mode
In Central Mode the microphones are switched on and off by an operator from a control
unit - usually under the direction of the meeting chairman.
To request the floor, press (and release) the REQUEST button on the unit. The integral
LED indicator will illuminate green to confirm that the request has been lodged at the
control unit. It is possible to subsequently cancel a request if desired by pressing this
button a second time, whereupon the indicator will extinguish. Should the indicator
extinguish without being cancelled in this way, the request will have been cancelled by the
operator.
If called to speak, the indicator will change to red, and the microphone will become "live".
The microphone luminant will also illuminate.
When speaking, a distance of at least 25cm (10 inches) should be maintained between
mouth and microphone. It not necessary to lean over the microphone and attempt to talk
directly into it; in fact this is likely to result in overloading and distortion. Speakers should
avoid turning their heads away from the microphone as pickup will be diminished.
Operating Instructions
Envoy System Operation Manual 4-5
The units incorporate a "cough" facility. This means that if required, the microphone can
be temporarily inhibited by pressing the REQUEST button. The red indicator extinguishes
and the microphone will be inoperative while the button is held down. This only works in
Central Mode.
If the chairman’s priority facility is used to interject while a delegate is speaking, all live
microphones will be temporarily inhibited until priority is released.
Microphones are switched off by the operator when delegates have finished speaking.
Nb: The system may be programmed to reject requests from certain (or even all) delegate
units. On these units the green indicator will flash on briefly when the button is pressed
then immediately go out. Conversely, the system can be programmed to allow certain
"VIP" units to bypass the request process and be turned on and off directly under the
control of the delegates. Refer to the operating manual for the central control unit(s) for
further information.
The maximum number of live delegate microphones permitted when operating in Central
Mode is sixteen. Chairman units are not restricted so the actual limits are twelve
delegates plus (up to) three chairman microphones live at any time.
4.2.3 Speech Timer Indication
When used in conjunction with the Manual Switching Units’ (CPM-401/2 etc.) speech
timer function, the current speaker’s microphone luminant will flash during the final minute
of his speech.
4.2.4 Voting
The units are equipped with three voting buttons, incorporating LED indicators. The
functions (and corresponding legends) are For (+), Abstain (0) and Against (-).
When a vote is started, the indicators in the voting switches will start to flash. The required
vote selection can then be made, and this is confirmed by the corresponding indicator
illuminating steadily.
Delegates may change their vote at any time during a voting period, the selection made
when the vote is closed is taken as the final one.
During a Secret Vote, the vote indicator LEDs will only illuminate briefly while the vote
button is pressed. Once released, all the voting LEDs will illuminate steadily to denote that
a vote has been registered.
Any microphones that were live at the start of the vote will remain active - unless the
operator cancels them. Microphones can be turned on and off by the operator during
voting and it is also possible to make and cancel requests.
Operating Instructions
Envoy System Operation Manual 4-6
4.3 CHAIRMAN UNIT
The Chairman Unit provides special microphone facilities and is intended for use by the
person presiding over the meeting.
4.3.1 Microphone Operation
The chairman unit does not make requests. The microphone is always activated directly
by the MIC/PRIORITY switch, regardless of operating mode (Central or Delegate). The
microphone is turned on when the button is pressed for the first time, and off when
pressed a second time (i.e. the same as the delegate units when in Delegate Mode).
4.3.2 Priority Facility
This is mainly what differentiates the chairman unit from normal delegate units. When
Priority is engaged, the chairman microphone is enabled, but any other active delegate
microphones in the system are turned off, and no delegate microphones can be turned on
while it remains in force. This is useful for restoring order in a meeting.
The Priority function is engaged by pressing and holding down the MIC/PRIORITY
button for more than a second or two. The red indicator incorporated in the button
flashes while Priority is engaged. Priority is relinquished once the button is released,
and the microphone also turns off.
4.3.3 Central/Delegate Modes
Any Central Control Unit connected to the system (PC or MSU) will record any units
turned off when the chairman's priority is engaged, and will restore them when priority is
released. This happens regardless of whether the system is operating in Central or
Delegate Mode. If there is no central control unit on-line, delegate microphones turned off
when priority is invoked will not be restored afterwards. The reasoning behind this is that if
there is no central control unit, judicious use of the priority function by the chairman can
prevent problems caused by delegates accidentally leaving their microphones on when
they have finished speaking. Otherwise it is assumed that the operator takes responsibility
for this task.
4.3.4 Voting
In general, voting facilities for the chairman are similar to those for the delegates.
4.3.5 Multiple Chairman Units
It is possible to have up to three chairman units on the system at a time. The additional
units will be pre-programmed with unique addresses*. All units have equal status and will
not be affected by Priority being invoked on another chairman unit.
5.0 INSTALLATION
Please read this section carefully before use as some of the following information
relates to the safe operation of the equipment.
5.1 DSC NETWORK CONTROLLER
5.1.1 Mains Power Supply
The mains supply to the DSC can be nominally either 115 or 230VAC. The equipment is
designed to operate from supplies within ±10% of the specified supply voltage, and
frequency in the range 50-60Hz. The setting for the unit is determined by the voltage
selector switch on the rear panel of the unit. Ensure that the operating voltage stated is
in accordance with the supply to be used.
The following procedure describes how the operating voltage can be changed to the
alternative setting, if necessary.
1. Ensure that the unit is completely disconnected from the mains supply, and from
any other equipment.
2. Locate the voltage selector switch on the rear panel, above the mains inlet.
3. Slide the actuator fully across to the required position. A tool may be required to
achieve this (e.g. small screwdriver or ball point pen).
4. Change the mains fuse in the rear panel holder to the correct value for the new
supply voltage (see Maintenance section). Amend the rating plate on the rear
panel (where applicable) to show the new operating voltage.
A mains lead is supplied with the unit terminated in an IEC320 connector. The other end
may be fitted with a moulded plug according to local market requirements, if known.
Alternatively, an unterminated lead may be supplied. This should be connected to a
suitable mains outlet observing the following wiring code:
The unit MUST
be earthed.
DSCs are microprocessor based. As with most equipment of this nature, a clean, reliable
mains feed is required. The discussion system should preferably be supplied from a
separate feed direct from the incoming mains distribution board. A clean "technical earth"
is also advisable. Normal precautions should be taken to avoid the possible introduction of
earth loops that could give rise to interference on the audio signals. These include
ensuring that all equipment in the system shares the same mains earth. Metal panels
Envoy System Operation Manual 5-1
Installation
(fixed systems) are earthed via the network wiring and should not be separately
connected to mains earth.
It is sometimes more convenient to leave all units in a system turned on and switch the
mains supply to the equipment rack via a single breaker. Note however that the inrush
current taken by high powered equipment such as the DSC50/100, APU, and most audio
amplifiers can be many times the rated continuous current. Breakers and fuses should be
rated accordingly.
5.1.2 Mounting
The DSC will often be used as a free standing unit if fitted with the optional protective
sleeve. Alternatively, it can be mounted in a 19” rack or cabinet along with associated
equipment.
However it is mounted, there must be adequate airflow to allow the unit to dissipate heat.
In particular, airflow around the top and bottom ventilation slots should not be obstructed
(e.g. by standing on carpet or mounting other equipment immediately above and below).
Excessive temperature rise can shorten the life of some components and cause
degradation which may lead to failure – possibly leaving them in a dangerous condition.
This applies not just to the DSC, but also to other equipment which may be installed in a
cabinet. Therefore, it is important that the cabinet itself is adequately vented.
The DSC is a relatively heavy unit, and slide rails must be used to support the unit if fitted
within a cabinet. The front panel fixings alone must not be relied upon to support the
weight of the unit. If the cabinet is to be transported, the DSC should ideally be removed,
and packed separately. If this is not feasible, a retaining bar should be fitted above the
unit to prevent movement in that direction. The cabinet should then be securely packed
and transported on its rear side so that the unit is suspended from its front panel.
The above comments also apply to Auxiliary Power Supply units and other heavy items
of equipment – e.g. audio and induction loop (AFILS) amplifiers.
5.1.3 Delegate Network Connections
Connection to the Delegate Network is via four zone connectors. These are of the 7-pin
DIN type incorporating a latching mechanism to prevent accidental disconnection.
Portable systems are usually straightforward. Delegate (and chairman) units simply plug
together, using extension cables as required. In fixed systems however, some installation
cabling will normally be required. If four, or less, network cables are involved, they can be
terminated directly in the 7-pin DIN plugs normally supplied with the DSC. If more, they
will either connect via a termination cabinet, or into one or more Auxiliary Power Supply
Units.
Wherever possible, take care to evenly distribute the total number of units evenly on the
available zones. For example, with 40 units connected to a DSC50, aim to connect 10 to
each zone. Internally, this unit has a split power supply, with 50% of the total power being
available on zones 1 & 3, and the other 50% on zones 2 & 4. Thus, one should certainly
aim for a 50:50 split across these two zone groups if the system is approaching the
maximum capacity of 50 units. For smaller systems, say 15 units or below, this is not
necessary.
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