ASL INTERCOM PS 6379 Mk2 User manual

January 2017 - V1.0
PS 6379 MK2
SIX CHANNEL
MASTER SPEAKER STATION
User Manual

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Table of contents
1.0!SAFETY*INSTRUCTIONS*..............................................................................................*3!
2.0!GENERAL*DESCRIPTION*.............................................................................................*5!
3.0!UNPACKING*..............................................................................................................*7!
4.0!WARRANTY*...............................................................................................................*7!
5.0!INSTALLATION*..........................................................................................................*7!
6.0!MAINS*POWER*&*SAFETY*EARTH*...............................................................................*8!
7.0!FRONT*PANEL*CONTROLS*&*CONNECTOR*..................................................................*9!
8.0!REAR*PANEL*CONNECTORS*&*SWITCHES*.................................................................*19!
9.0!INTERNAL*CONTROLS*..............................................................................................*22!
10.0!IFB*FUNCTION*.........................................................................................................*24!
11.0!DIP*SWITCHES*.........................................................................................................*25!
12.0!TECHNICAL*SPECIFICATIONS*....................................................................................*26!
13.0!PARTY*LINE,*TECHNICAL*CONCEPT*...........................................................................*28!
14.0!CABLING*.................................................................................................................*28!
15.0!SYSTEM*CONFIGURATION*.......................................................................................*31!
11.0!EARTHING*CONCEPT*...............................................................................................*32!

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1.0 SAFETY INSTRUCTIONS
Please always follow these instructions to help ensure against injury to yourself
and/or damage to the system!
1. Read all safety and operating instructions before you operate the apparatus.
2. Retain all safety and operating instructions for future reference.
3. Heed all warnings on the apparatus and in the operating instructions.
4. Follow all installation, operating and use instructions.
5. Unplug the apparatus from the AC power outlet before cleaning. Use only a
damp cloth for cleaning the exterior of the apparatus.
6. Do not use accessories or attachments not recommended by the manufacturer,
as they may cause hazards and void the warranty.
7. Do not operate this apparatus in high humidity areas or expose it to water or
moisture.
8. Do not place the apparatus on an unstable cart, stand, tripod, bracket or table.
The apparatus may fall, causing serious personal injury and damage to the ap-
paratus.
9. Do not block or cover any openings in the apparatus. These are provided for
ventilation and protection from overheating. Never place the apparatus near
any heat sources such as radiators, heat registers, stoves, or other apparatus
(including amplifiers) that produce heat. Do not place the apparatus in an en-
closure such as a cabinet without proper ventilation.
10. If the apparatus is mounted in a 19” rack, make sure that sufficient space around
the unit (sides, top, and bottom) is provided to ensure free circulation of air.
11. Operate the apparatus using only the type of power source indicated on the
marking label. Unplug the apparatus’ power cord by gripping the power plug,
not the cord.

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12. Insert the mains plug properly. Do not defeat the safety purpose of the polar-
ized or grounding-type plug. An American polarized AC line plug has two blades
with one wider than the other. This plug will fit only one way into the power
outlet. This is a safety feature. If you are unable to insert the plug fully into the
outlet, try reversing the plug. If the plug still fails to fit, contact an electrician to
replace the obsolete outlet. 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 to
replace the obsolete outlet.
13. Route power supply cords so that they are not likely to be walked on or pinched
by items placed upon or against them. Pay attention to cords at plugs, conven-
ience receptacles, and the point where they exit from the apparatus.
14. Do not overload wall outlets or extension cords, as this can result in a risk of fire
or electrical shock.
15. Unplug this apparatus during lightning storms or when unused for long periods
of time.
16. Never insert objects of any kind into the apparatus through openings, as the
objects may touch Dangerous voltage points or short out parts. This could cause
fire or electrical shock.
17. Refer all servicing to qualified service personnel. Servicing is required when the
apparatus has been damaged in any way, such as when the power-supply cord
or plug is damaged, liquid has been spilled or objects have fallen into the appa-
ratus, the apparatus has been exposed to rain or moisture, does not operate
normally, or has been dropped.!

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2.0 GENERAL DESCRIPTION
The PS 6379 Mk2 is a master loudspeaker station with 6 intercom channels and a built-in
power supply, offering full duplex communication with analog remote stations.
The unit incorporates a loudspeaker, a gooseneck microphone and an XLR-4 headset con-
nector.
As an option, an XLR-6 headset connector can be fitted for binaural (split ear) use of the
headset.
By setting internally mounted jumpers, each of the 6 channels can be assigned to either
the left or the right headset can, or to both headset cans.
If the gooseneck microphone is active the loudspeaker is automatically attenuated.
The degree of attenuation can be adjusted by a trimmer at the front panel. If a headset is
connected, both gooseneck microphone and speaker are switched off automatically.
The loudspeaker can be switched on again by pushing the Speaker on/off button.
The PS 6379 Mk2 has newly designed mic input circuits with a proprietary limiter allowing
to speak close and/or loud into the headset or gooseneck microphone without giving rise
to overload and distortion
The unique CALL system provides both a flashing red LED and a very distinctive sound
signal (buzzer). The volume of the buzzer can be adjusted by a trimmer on the front panel.
Front Panel Features (for each channel):
• a TALK button with built-in green LED,
• a CALL button with built-in red LED,
• a Channel Volume control with “channel on/off switch”,
• buzzer and mic mute buttons
• an AUX Volume control
• NULL ADJUST trimmers
• an LED to indicate overload
• an LED to indicate a system link connection.
If TALK or CALL buttons are not active, they are lit in a white color, allowing to easily find
these buttons in a dark environment. The light intensity of this so-called “backlight” can
be adjusted (see Master Section Features).

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IFB function:
Two channels of the PS 6379 Mk2 can be programmed to be so-called IFB (‘Interrupt Fold-
back’) channels, used for one way communication from i.e. a director/producer to a “tal-
ent” (e.g. a reporter or show presenter) in a broadcast environment. (see section 10.0)
The talent has a headphone or an earpiece, connected to an analog IFB receiver or stand-
ard analog beltpack.
Front Panel Features (Master Section):
• a CALL TO TALK button
• a TALK TO ALL button
• a STAGE ANNOUNCE button
• a SPEAKER ON/OFF button
• a PGM (Program) Volume knob
• a MASTER VOLUME knob
• an “OWN VOICE” control knob
• an ALL MICS MUTE button
• an ALL BUZZERS MUTE button
• trimmers for buzzer volume, loudspeaker attenuation, IFB Dim factor and back-
light intensity
• LEDs to indicate System Overload, DC power and Mains power.
Rear Panel Features:
• Intercom Line and System Link connectors for each channel
• Connectors for Stage Announce audio output and Stage Announce relay
• three electronically balanced auxiliary (AUX) audio inputs with ground lifts
• AUX routing switches for each channel
• an electronically balanced PGM input with ground lift switch
• switches for putting channel E and F into IFB mode
• a connector for an external loudspeaker
• Mains and DC inlet connectors
Power Supply:
The built-in 105 Watt (3.5 A) switch mode power supply is protected against a too high
temperature and can easily drive up t 30 Pro Series beltpacks or 15 Pro Series 2-ch
speaker stations, or a combination of both.
The current on each channel is limited to 1.3 A, allowing to connect 10 Pro Series beltpacks
or 5 Pro Series 2-ch speaker stations to a channel, or a combination of both.

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In case AC mains is not available, the unit may be powered by an external DC power
source (24 – 30V) which can provide 105 watts.
3.0 UNPACKING
The shipping carton contains the PS 6379 Mk2, a power cable, 2 fuses and a 19” rack
mounting kit. After unpacking the unit please inspect for any physical damage to the unit
and retain shipping carton and relevant packing materials for use should the unit need
returning.
If any damage has occurred, please notify your dealer so that a written claim can be initi-
ated. Please also refer to the warranty section of this user manual.
4.0 WARRANTY
This unit is warranted by ASL Intercom to the original end-user purchaser against defects
in workmanship and materials in it’s manufacture for a period of 12 months from date of
shipment to the end-user. Faults arising from misuse, unauthorized modifications or ac-
cidents are not covered by this warranty. If the unit is faulty, it should be sent in its original
packing to the supplier or local ASL dealer, with shipping prepaid. A note must be included
stating the faults found and a copy of the original supplier’s invoice.
5.0 INSTALLATION
Adequate ventilation must be provided by allowing sufficient space around the sides and
rear of the unit to ensure free circulation of air. Forced cooling is not required. The power
supply is mounted on the bottom of the unit. After a period of time the unit will feel hot
to the touch at the top and the bottom; this is normal and should be no cause for alarm.
To connect the PS 6379 Mk2 to the user stations, use professional flexible microphone
cable with 2 wires and 1 shield only.
Connect these cables to the INTERCOM OUT connectors on the rear panel.

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The PS 6379 Mk2 is fully protected against wiring mistakes (e.g. reverse power) or short
circuit in the interconnect cables. Included in the shipping carton is a kit for mounting the
unit in a 19" rack, taking 2U of rack-space.
6.0 MAINS POWER & SAFETY EARTH
WARNING: This appliance must be earthed!
Connecting to mains power:
The PS 6379 Mk2 may be connected to a mains power outlet which provides 100 – 240 V
AC, 50-60 Hz, 200 watts. The outlet should have a clean earth. Avoid using mains power
outlets which also power dimmer controlled lighting equipment.
The wires in the mains lead are color coded:
green/yellow: Earth / safety ground
blue: Neutral
brown: Live
• The wire which is colored green/yellow must be connected to the terminal in the
plug which is marked with the letter “E”, or by the ground symbol, or is colored
green. The wire which is colored blue must be connected to the terminal which is
marked with the letter “N” or colored black.
• The wire which is colored brown must be connected to the terminal which is
marked with the letter “L” or colored red.
Safety Earth:
For personal safety and proper operation of the PS 6379 Mk2 and connected stations the
green/yellow wire of the mains lead must always be connected to the electrical installation
safety earth or ground.
This wire is in the PS 6379 Mk2 connected to all exposed metal surfaces. Any rack frame-
work into which this unit might be mounted is assumed to be connected to the same
grounding circuit.
Switching On:

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To limit the inrush current after the PS 6379 Mk2 has been switched on, 30 V DC line
power is provided to the intercom channels, one after the other. If a channel is found to
have too many stations being connected or in case of short circuit, a circuit breaker im-
mediately shuts off that channel from 30V DC line power. If the total amount of to the PS
6379 Mk2 connected user stations is found to exceed the allowed maximum (see section
2.0), a “master circuit breaker” shuts off the line power to all channels.
7.0 FRONT PANEL CONTROLS & CONNECTOR
1 TALK buttons
Pushing these buttons allow talking to each channel separately or to some or all channels
simultaneously. If a TALK button is switched on, its large green LED is lit.
By pushing and holding the TALK button of a so-called IFB channel (see section 10.0), the
TALK buttons of the intercom channels switch automatically off. To talk to an IFB channel
and additionally to a intercom channel, one has to also push and hold the TALK button of
that intercom channel.
To achieve that one can talk to an IFB channel and to all intercom channels of which the
TALK buttons are enabled (the corresponding Talk LEDs are lit), the position of a certain
DIP switch must be changed. See section 11.0, DIP switch A.

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Momentary switching:
If a TALK button is pushed and held, the microphone signal is sent to the referring inter-
com channel until the button is released.
Latched switching:
If a TALK button is pushed shortly, it is electronically latched and the microphone signal is
sent to the referring intercom channel.
If pushed again, the TALK button switches off. For each channel the latch function can be
disabled by changing the position of certain DIP switches (see section 11.0, DIP switch
group E). The TALK button is then “momentary only”.
2 CALL button
To activate the call system, for each channel separately. By a momentary push a visual
CALL signal is sent to all stations connected to the referring intercom channel and the call
LEDs start flashing. By holding the CALL buttons for 2 seconds the buzzers are activated,
provided there is no buzzer mute status on that channel. After the CALL button is released
the LEDs continue to flash for a further 2 seconds. The CALL function of a channel in IFB
mode is automatically disabled.
3 NULL ADJUST trimmers
With these trimmers (one set for each channel) one may minimize the speaker feeding
back into the gooseneck microphone (unit feedback) and for minimizing the headset mic
feeding back into the headset can(s); the LOW trimmer is for all frequencies, the HIGH
trimmer solely for the high frequencies.

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Null Adjustment procedure, for each channel separately:
• turn the ‘Own Voice” (side tone) control knob to minimum
• set Null Adjust trimmers in start position: fully clockwise.
• switch off the microphones of all connected (speaker-) stations
• make sure that there is no automatic speaker attenuation (turn trimmer #21 fully
clockwise)
• push the TALK button of the channel to be null adjusted
• slowly turn up the listen volume of the PS 6379 Mk2 (channel + master volume)
• speak into the gooseneck microphone
• adjust the speaker listen level to a minimum by turning the null adjust trimmers
counter clockwise (first the LOW trimmer and then the HIGH trimmer; repeat this a
few times)
• Connect a headset (the loudspeaker and gooseneck mic are now automatically dis-
abled) and speak into the headset microphone. Check whether the level of your
voice in the headset can(s) is sufficient. If not, push this level up by turning the
OWN VOICE knob ( #4) clockwise.
The operating area of the Null Adjust trimmers is between fully clock-wise and minimum
level.
Should the number of user stations on a channel and/or the length of the party line ca-
ble change, the null for that channel has to be adjusted again.

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4 OWN VOICE control knob
With this knob one adjusts the extent to which the headset mic signal is heard in your
headset cans.
5 CHANNEL VOLUME knob
To adjust the listen level of the corresponding channel. Turning a knob fully counter-clock-
wise switches that channel off (the channel is disabled, see also #6).
For as long as the TALK button of an IFB channel is kept pushed, the Listen function of
the intercom channels is automatically disabled. To achieve that these Listen functions
are not disabled if an IFB TALK button is pushed, the position of a certain DIP switch has
to be changed. See section 11.0, DIP switch B
6 CHANNEL ON LED indicator
This green LED is lit when the corresponding channel is switched on. In case the channel
is switched off by the CHANNEL VOLUME knob (#5), its TALK, CALL and LISTEN controls
are disabled. (Line power to the channel remains).
7 MIC MUTE button
By pushing this button the TALK button of the corresponding PS 6379 Mk2 channel is
disabled, by which also the TALK buttons on remote stations are disabled (the ones of the
remote station channels which are connected to the corresponding PS 6379 Mk2 chan-
nel).
A disabled TALK button can be enabled again by pushing it. The MIC MUTE button of a
channel in IFB mode is automatically disabled
8 BUZZER MUTE button
By pushing this button the buzzers of all stations connected to the corresponding (party
line) channel can be remotely muted. After being pushed the Buzzer Mute button is lit.
The buzzers remain being muted until the BUZZER MUTE button is switched off again (the
Buzzer Mute status is abolished).
The BUZZER MUTE button of a channel in IFB mode is automatically disabled.

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9 AUX Volume knob
By turning this knob one adjusts the level of the auxiliary signal as sent to the correspond-
ing channel. The AUX signal may originate from either AUX input 1, AUX input 2 or AUX
input 3 (see AUX inputs #34 and AUX select switches #35)
10 SYSTEM LINK LED
This yellow LED illuminates if a channel of another ASL Intercom System has been con-
nected to the PS 6379 Mk2 through the “System Link” connector (#33) of the correspond-
ing channel. The “other system” channel is now the MASTER channel and the ‘linked’ PS
6379 Mk2 channel the SLAVE channel (The line impedance is now provided by the MASTER
channel and the line impedance of the SLAVE channel is switched off). One can talk, listen
and call to and from all user stations which are connected to the MASTER channel and to
the SLAVE channel.
A Mic Mute signal sent from the MASTER channel to the SLAVE channel is also received by
the user stations on that channel. But a Mic Mute signal sent from the PS 6379 Mk2 is only
received by the user stations on its own channels (it does not mute the microphones of
the user stations on the MASTER channel)
A Buzzer Mute signal on the MASTER channel is received by the user stations on that
channel and by the user stations on the SLAVE channel.
A SLAVE channel is not able to generate a Buzzer Mute signal (the Buzzer Mute button of
the SLAVE channel is disabled).

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11 ON/OVERLOAD LED
This LED is lit green when 30 V DC line power is supplied to the corresponding channel.
The LED is lit red when too many user stations have been connected to the corresponding
channel or if there is a short circuit on that channel. A circuit breaker immediately discon-
nects the line power from that channel and resets (restores line power) automatically
within 2 seconds after the cause of the overload has been removed.
12 IFB MODE LED indicator (for channels E and F only)
This yellow LED is lit if the channel is put into IFB mode, see section 10.0
13 TALK TO ALL button
By pushing and holding this (momentary only) button one may talk to all intercom chan-
nels simultaneously. The green LEDs in the TALK buttons of all channels light up, except
for the LEDs in the TALK buttons of the channels in IFB Mode. To also include the TALK
buttons of the channels in IFB Mode, the position of certain DIP switches must be changed
(see section 11.0, DIP switch C).
14 CALL TO TALK button
By shortly pushing this (momentary only) button a visual Call signal is simultaneously sent
to all channels of which the TALK buttons are switched on. All corresponding Call LEDs of
the PS 6379 Mk2 (except the ones of the channels in IFB Mode) and of all connected sta-
tions start flashing. When holding the CALL TO TALK button pushed for 2 seconds the
buzzer is activated, should no buzzer mute be activated for that channel.After the CALL
TO TALK button is released the LEDs continue to flash for a further 2 seconds.

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15 MASTER VOLUME knob
By turning this knob one adjusts the volume of the sum of all intercom signals as heard
in the loudspeaker and/or headset. This knob may also adjust the master volume control
for both the intercom and the PGM (Program Audio) signals, depending on the position
of jumpers #44.
16 PGM VOLUME
By turning this knob one adjusts the listen volume of the PGM input. The signal of the
PGM input can only be heard on the speaker and/or headset of the PS 6379 Mk2 and does
not appear on the intercom lines.
If a TALK button is pushed and the speaker is On, the speaker is automatically attenuated.
This diminishes the effect that the PGM signal goes from the speaker into the micro-
phone).
The position of jumpers #44 determine whether the program audio listen level is also
controlled by the Master Volume knob (#15).
17 STAGE ANNOUNCE button
By pushing this button the microphone signal is directly routed to the line level output at
the rear panel. The microphone signal (the ‘Announce’) is not sent to the intercom chan-
nels. Whilst the Stage Announce button is kept pushed, the channel TALK buttons are
disabled (the built-in LEDs extinguish if they were lit before) and the speaker is automati-
cally switched off. To achieve that the speaker is not automatically being switched off, the
position of a certain DIP switch must be changed. See section 11.0 DIP switch D).
18 SPEAKER ON/OFF button

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With this button the loudspeaker can be switched on or off. The LED in the button is lit
when the speaker is switched on. As soon as a headset is plugged in, the speaker is auto-
matically disabled (if it was enabled before). By pushing the speaker on/off button, the
speaker is enabled again and the audio can be heard over both the speaker and the head-
set. When unplugging the headset, the speaker setting (on or off) is as before the headset
was plugged in.
19 ALL MICS MUTE button
By pushing this button the TALK buttons of the PS 6379 MK2 and the TALK buttons of the
connected remote stations are disabled
(if they were previously enabled). After the ALL MICS MUTE button is being pushed, it is lit
for a few seconds. Also all channel MIC MUTE buttons (#7) are lit for a few seconds.
Disabled TALK buttons (on the PS 6379 MK2 or on a connected remote intercom station)
can be enabled again by pushing them.
20 ALL BUZZERS MUTE button
By pushing this button the buzzers of the connected stations and of the PS 6379 Mk2 can
be muted. After being pushed, all channel Buzzer Mute buttons (#8) are lit. The buzzers
remain being muted until the ALL BUZZER MUTE button is switched off again (the buzzer
mute status is abolished). The channel Buzzer Mute buttons return to their previous sta-
tus (the ones which were lit before the ALL BUZZER MUTE button was pushed remain
being lit).
21 SPEAKER ATTENUATOR trimmer

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To adjust the extent to which the loudspeaker is automatically dimmed when the goose-
neck microphone is switched on. It prevents unit feedback if Null Adjust is not sufficient.
It also minimizes system feedback or a 'hollow' sound when the gooseneck microphones
of other speaker stations (on one or several of the connected party lines) are switched on
as well.
Adjustment procedure :
• make sure that there is no headset connected
• switch off all TALK buttons of the PS 6379 Mk2.
• feed an audio signal to an intercom channel (see #9 and #34)
• turn up the listen volume of the PS 6379 Mk2 (selected channel and master volume)
• activate the gooseneck microphone (push the TALK button of the selected channel)
• adjust the desired degree of speaker attenuation (turning the trimmer counter-
clockwise increases the attenuation)
22 BUZZER VOLUME trimmer
To adjust the volume of the internal buzzer.
23 IFB DIM FACTOR trimmers
By turning these trimmers, the IFB DIM factor for channel E and channel F can be set,
should these channels being put into IFB Mode (see switches #36). The IFB Dim Factor is
the extent to which the AUX signal is dimmed (0% to 100%) when pushing the TALK but-
ton of a channel which is put into IFB mode. If the knob is fully clockwise, the DIM factor
is at its maximum (100% dimming).
24 BACKLIGHT trimmer
If TALK or CALL push buttons are not active, they are lit white allowing to easily find these
buttons in a dark environment. By turning this trimmer the light intensity can be adjusted.
25 Master OVERLOAD LED indicator
As soon as more than the allowed maximum allowed user stations are connected to the
PS 6379 Mk2 (the current from the built-in PSU is in danger to exceed 5A) the red Overload
LED is lit and a circuit breaker disconnects the line power from all channels. The circuit-
breaker resets (restores line power) automatically 3 seconds after the cause of the over-
load has been removed. The LED also lights up red - for a few seconds - every time mains
power is switched on.
26 MAINS LED indicator

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If mains power is switched on (see #31 ‘Mains Power On/Off switch’) this green LED is lit.
27 DC power LED indicator
If the DC input on the rear panel (see #41) receives DC power (24 – 30V / 5A) this yellow
LED is lit.
28 HEADSET connector
To this XLR-4 connector of a headset can be connected. The headset must have a can
impedance of minimum 200 ohms. If the headset has two cans in parallel, each can must
have an impedance of minimum 400 ohms.
The headset microphone may be of the dynamic or electret type. .A limiter prevents the
mic pre-amp from clipping when speaking close or loud into the headset microphone.The
gain for the headset mic can be adjusted by trimmer #45.
Headset connector pin assignments:
Pin 1. Shield mic. (GND)
Pin 2. mic. +
Pin 3. phones +
Pin 4. phones -
When a headset is connected, speaker and gooseneck microphone are disabled automat-
ically. The speaker can be enabled again by pushing the SPEAKER on/off button (#18).
The PS 6379 Mk2 can optionally be equipped with an XLR-6 headset connector for binau-
ral use of the headset. Internal jumpers determine - for each channel separately - the
routing of the audio to the headset cans: either to the left can, or to the right can or to
both cans.
(See #43 ‘Binaural Jumper Settings’).
29 GOOSENECK microphone
This is an electret noise cancelling microphone.
A limiter prevents the mic pre-amp from clipping when speaking close and/or loud into
the microphone. The microphone is automatically disabled when a headset is connected
to the PS 6379 Mk2. The mic gain can be adjusted by trimmer #46
30 LOUDSPEAKER
A high quality 16 Ωloudspeaker. The speaker is automatically disabled if a headset is con-
nected. It can be switched on again by pushing the SPEAKER On/Off button (#18).

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31 POWER ON/OFF push button
To switch the internal power supply On or Off.
8.0 REAR PANEL CONNECTORS & SWITCHES
32 INTERCOM OUT connectors (one per channel)
These male XLR-3 connectors are for connecting the intercom party lines to which remote
stations can be connected, via standard microphone cable.
Pin assignment:
Pin 1: 0V / ground
Pin 2: +30 V power wire
Pin 3: Audio wire
33 SYSTEM LINK connectors (one per channel)
34 AUX INPUT connectors + ground lift switches
These three XLR-3 female connectors are inputs for auxiliary (AUX) audio signals.
The inputs are electronically balanced and accept line level audio signals. For routing
these AUX signals to the intercom channels, see #35.
Pin assignment of all AUX input connectors:
Pin1. 0V / ground

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Pin 2. Signal +
Pin 3. Signal -
35 AUX SELECT switch (one per channel)
A 3-position switch to route either AUX 1 or AUX 2 or AUX 3 to the corresponding channel
34 AUX INPUT connectors + ground lift switches
These three XLR-3 female connectors are inputs for auxiliary (AUX) audio signals.
The inputs are electronically balanced and accept line level audio signals. For routing
these AUX signals to the intercom channels, see #35.
Pin assignment of all AUX input connectors:
Pin1. 0V / ground
Pin 2. Signal +
Pin 3. Signal -
35 AUX SELECT switch (one per channel)
A 3-position switch to route either AUX 1 or AUX 2 or AUX 3 to the corresponding channel
36 IFB mode switches E and F
To put channel E and/or F into IFB mode
37 PGM INPUT connector + ground lift
This XLR-3 female connector is an electronically balanced input for line level audio signals.