ASL INTERCOM PS 230 User manual

PS 230
DUAL CHANNEL
REMOTE SPEAKER STATION
USER MANUAL
October 2013
This product is designed and manufactured by:
ASL Intercom B.V.
Zonnebaan 42
3542 EG Utrecht
The Netherlands
Phone: [phone]
Fax: [phone]
E-mail: [e-mail]
Web: www.asl-inter.com

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User Manual PS 230 / October 2013 © ASL Intercom BV
CONTENT OF THIS USER MANUAL
1.0 GENERAL DESCRIPTION.......................................................................3
2.0 INSTALLATION........................................................................................3
3.0 FRONTPANEL CONTROLS & CONNECTORS.......................................3
5.0 INTERNAL CONTROLS...........................................................................5
6.0 TECHNICAL SPECIFICATIONS..............................................................6
7.0 PS 230 BLOCK DIAGRAM.......................................................................6
8.0 PARTY LINE, TECHNICAL CONCEPT....................................................7
9.0 CABLING..................................................................................................7
10.0 EARTHING CONCEPT ............................................................................8
11.0 SYSTEM CONFIGURATION....................................................................8

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User Manual PS 230 / October 2013 © ASL Intercom BV
1.0 GENERAL DESCRIPTION
The PS 230 is a dual channel speaker station
designed for use in an ASL analog intercom
system and provides full duplex communications.
The unit incorporates a loudspeaker, a
gooseneck microphone and a headset connector
The PS 230 RM model has, instead of a
gooseneck mic, a small built-in electrets mic.
Each channel has Volume (listen level) Control, a
TALK and CALL button with LED indicators and a
2-stage side tone trimmer. There is a trimmer for
speaker attenuation and one for buzzer volume.
The unit is equipped with a limiter for the
gooseneck microphone, allowing the user to
speak close into the microphone without giving
rise to overload and distortion.
Loudspeaker dimming is automatic if the
gooseneck microphone is active.
Private conversation may be carried out via a
headset or telephone handset plugged into the
headset connector. If a headset is connected,
both the gooseneck microphone and speaker are
disabled automatically.
The XLR-4 headset connector can be replaced
(by ASL) by a XLR-6 connector for binaural use of
the headset.
Special attention has been paid to the intelligibility
of speech. By applying low noise/high speed op-
amps, a speech presence filter and a specially
developed high power bridged headphone
amplifier, communication is very comfortable even
in environments with high back-ground noise
level. There is a separate amplifier for the
loudspeaker.
The unique ASL CALL system provides both a
flashing red LED and a very characteristic sound
signal (the buzzer). Smooth operation is
guaranteed with the CALL button. Only a slight
touch makes the red LED flash, whilst holding the
button for two seconds activates the CALL sound
signal. The volume of this signal (the buzzer) can
be adjusted at the front panel.
Fully electronic switching allows for 'soft'
microphone on switching (latching or momentary),
remote Mic Mute facility and automatic speaker
attenuation.
2.0 INSTALLATION
Connect the intercom party lines to the LINE
connectors on the side panel of the PS 230.
The necessary DC voltages are derived from a
master station or a separate power supply, via the
intercom connection cables. Use professional
microphone cable with 2 wires and 1 shield only.
The PS 230 is fully protected against wiring
mistakes (reverse power) or short circuit in the
interconnecting cables.
A kit is available for mounting the PS 230 in a 19"
rack, taking 2U of rack space.
3.0 FRONTPANEL CONTROLS & CONNECTORS

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User Manual PS 230 / October 2013 © ASL Intercom BV
1 VOLUME control knobs
To adjust the listen level for the headset and the
loudspeaker.
2 TALK buttons
To activate the gooseneck or headset
microphone. The large green LEDs indicate if the
microphone is ‘on’.
Momentary switching:
If a TALK button is pushed and held, the
microphone signal is sent to the corresponding
intercom 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 corresponding intercom channel.
If pushed again, the TALK button switches off.
Mic Mute if latched on:
After on the intercom channel a so-called MIC
Mute signal has been received from a PRO
Series master station or separate power supply,
the connection between microphone and intercom
channel is interrupted. By pushing the TALK
button the connection is restored again.
3 CALL buttons
These push buttons (one for each channel)
activate the call system.
By a momentary push a visual call signal is sent
to all stations connected to the corresponding
intercom channel and the call LEDs start flashing.
By holding a CALL button pushed for 2 seconds
the call buzzer is activated, provided there is no
‘buzzer mute’ on one or both intercom channels.
After the CALL button is released the LEDs
continue to flash for a further 2 seconds.
4 SIDE TONE LEVEL trimmers
These trimmers, one for each channel, are for
minimizing the speaker feeding back into the
gooseneck microphone (unit feedback). They also
determine the level of your own voice as you hear
it in the speaker or headset.
5 SIDE TONE HI trimmers
These trimmers, one for each channel, have the
same purpose as trimmer #5, but solely for the
high frequencies.
Adjustment procedure for both side tone
trimmers, for each channel separately:
•set trimmer in start position: fully clockwise
•switch off the microphones of all
connected (speaker) stations
•make sure there is no automatic speaker
attenuation (turn trimmer #6 fully
clockwise)
•push the TALK button of the
corresponding channel
•slowly turn up the listen volume
•speak into the gooseneck microphone
•adjust the speaker listen level of the
corresponding channel to a minimum by
turning the side tone trimmers counter
clockwise (first trimmer #4 and then
trimmer #5; repeat this a few times)
•Connect a headset to the PS 230 (the
speaker and gooseneck mic are now
automatically disabled) and speak into the
headset microphone
•Check whether the level of your voice in
the headset can(s) is sufficient. If not,
push up the listen level of the
corresponding channel a bit by turning
side tone trimmer #4 clockwise.
The trimmers operating area is between fully
clockwise and minimum level.
Adjusting the side tone does not affect the level of
your voice as it is heard by other stations.

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User Manual PS 230 / October 2013 © ASL Intercom BV
6 SPEAKER ATTENUATOR trimmer
To adjust the extent to which the speaker is
automatically dimmed if the gooseneck
microphone is switched on. It prevents unit
feedback if side tone rejection is not sufficient.
It also minimizes system feedback or a 'hollow'
sound when the gooseneck microphones of other
speaker stations on the intercom channel are
switched as well.
Adjustment procedure :
•make sure there is no headset connected
•feed an audio signal into one of the
intercom channels (via an AUX input on a
master station or a separate power
supply)
•turn up the listen volume
•activate the gooseneck microphone
•adjust the desired degree of speaker
attenuation (turning the trimmer counter-
clockwise increases the attenuation)
7 BUZZER VOLUME trimmer
To adjust the volume of the internal buzzer. The
buzzer is activated if a CALL button of the PS 230
is pushed (or a CALL button of any other station
on a channel to which the PS 230 is connected)
longer than 2 seconds, provided there is no
‘buzzer mute’ on one of the channels.
8 HEADSET connector (XLR-4)
To connect a headset to the unit. The headset
can must have an impedance of 200 ohms
minimum. When there 2 cans in parallel each can
must have an impedance of 400 ohms minimum.
The headset microphone may be of the dynamic
or electret type.
XLR-4 pin assignments :
Pin 1. Shield mic. (GND)
Pin 2. mic. +
Pin 3. phones +
Pin 4. phones
If a headset is connected, the speaker and
gooseneck microphone are disabled
automatically.
9 GOOSENECK MICROPHONE
An electret noise canceling gooseneck
microphone. A limiter prevents the microphone
preamplifier from clipping when speaking close
into the microphone
10 LOUDSPEAKER
A high quality 16 Ω loudspeaker
4.0 SIDE PANEL CONNECTORS
11 LINE connector channel A
12 LINE connector channel B
These connectors are for connecting the PS 230
to the party lines of an intercom system.
XLR-3 pin assignments :
1. 0 V /ground shield
2. +30V power wire
3. audio wire
5.0 INTERNAL CONTROLS
Inside the unit there are trimmers to adjust the
mic gain of the gooseneck microphone and the
headset microphone separately.
The trimmers are located on the PC board.
The trimmers can be reached as follows :
•remove the screws of the bottom plate
•slide the plate to one side and take it out
•take away the plastic isolation plate
The trimmers are labeled :
‘GOOSE’ for the gooseneck microphone
‘HEADS’ for the headset microphone

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User Manual PS 230 / October 2013 © ASL Intercom BV
6.0 TECHNICAL SPECIFICATIONS
System Specifications
Dynamic range: 80 dB (1 kHz, THD < 1%)
Frequency response: 200 Hz – 15 kHz (-3dB)
Call signal: (send): +2.8 mA
Call signal threshold (receive): +2.4V DC
Operation voltage: 24 – 32 V DC
Power interrupt time (Mic Mute): 0.1 sec
Line Impedance: 350 Ω (1 kHz), 2.2 kΩ (DC)
Audio level: nom. -18 dBu, max. 0 dBu
Microphone Pre-amps
Gain: 40 – 60 dB (adjustable internally, separately
for the headset mic and the gooseneck mic)
Presence filter: +6 dB @ 5 kHz
Power to electret mic: +9V DC
Limiter range (gooseneck mic): 30 dB
Headphone Driver Amp
Max. output level:
normal: 16 V rms (@ 200 Ω
binaural: 2x 10.3 V rms (@ 400 Ω
Max. output power:
normal: 1.3 W rms @ 200 Ω
binaural: 2x 0.27 W rms @ 400 Ω
Speaker Driver Amp
Max. output power: 1.6 W rms @ 16 Ω
Side Tone
Rejection: 0 -30 dB adjustable
Buzzer
Max. SPL: 85 dBA
PS 230 Power Consumption
Current (at 30V DC):
- 35 mA quiescent
- 70 mA signaling
- 190 mA at max. output + signaling
PS 230 Dimensions & Weight
Width 230 mm
Height 88 mm
Depth 42/48 mm sloping
Weight 1.3 Kg
0 dBu is defined as 775 mV into open circuit
ASL reserves the right to alter specifications
without prior notice.
7.0 PS 230 BLOCK DIAGRAM

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User Manual PS 230 / October 2013 © ASL Intercom BV
8.0 PARTY LINE, TECHNICAL CONCEPT
User stations in an ASL intercom system are connected via
one or several ‘party lines’. A party line offers two way
('full duplex') communication and consist of standard
microphone (multi-pair) cable. One wire is used as an
audio line, one as a power line and the screen of the
cable functions as earth/return.
Current drive is used for signal transfer. Each station
utilizes a current amplifier to amplify the microphone
signal and place it on the common audio line where,
due to the constant line impedance, a signal voltage is
developed which can be further amplified and sent to
headphones or loudspeakers.
This principle has three advantages:
1. the use of a single audio line allows several
stations to talk and listen simultaneously
2. due to the high bridging impedance offered by
each station, the number of stations on the
party line has no influence on the level of the
communications signal
3. power and audio to the intercom stations use
the same cable.
The Call signal is also sent as a current on the audio
line. It develops a DC potential over the line
impedance which is sensed by each station and
interpreted as a Call signal.
9.0 CABLING
The intercom lines (the ‘party lines’) are of the shielded two-conductor microphone cable type. The intercom line
connectors are of the XLR-3 type. Audio and Call signals are on pin 3, DC power is on pin 2 and pin 1 is connected to
the shield of the cable which functions as the common return for audio and power.
The audio signal is transferred in an unbalanced way (see Party Line, Technical Concept). To avoid earth loops
(hum), the possible effect of electromagnetic fields and to minimize power loss, certain rules have to be obeyed when
installing the cabling of an ASL intercom system.
Use high quality cable
Use high quality microphone cable (shielded two
conductor cable, minimum 2x 0.30 mm2).
In case multi-pair cable is used, each pair should
consist of two conductors (minimum 2x 0.15 mm2) with
separate shield and an overall shield.
Use flexible cable
Use flexible single and multi-pair microphone cable
instead of cable with solid cores, especially when the
cable is subjected to bending during operation or
installation.
Cable screens to XLR pin 1
The screen of each separate microphone cable and/or
the screen of each single pair in a multi-pair cable,
should be connected to pin 1 of each XLR-3
connector. Do not connect this cable screen to the
metal housing of ASL units or XLR-3 wall boxes.
See section ‘Earthing Concept’.
Connect cable trunks, connection boxes and
overall multi-pair cable screens to clean earth
Metal cable trunks, metal wall boxes and overall multi-
pair cable screens should be interconnected and, at
the 'central earth point' in the intercom network only,
be connected to a clean earth or a safety earth.
See section ‘Earthing Concept’.
Keep metal connection boxes and cable trunks or
pipes isolated from other metal parts
Metal trunks or pipes for intercom cables and metal
connector boxes should be mounted in such a way
that they are isolated from any other metal housing or
construction part.
Keep cables parallel as much as possible
When two (multi channel) units in a network are
connected by more than one cable, make sure that
these cables are parallel to each other over the whole
distance between those units. When using multi-pair
cable, parallelism is ensured in the best possible way.
Avoid closed loops
Always avoid that cables are making a loop. So-called
'ring intercom' should not physically be cabled as a
ring.
Keep cables away from electromagnetic sources
Keep intercom cables away from high energy cables,
e.g. 115/230/400V mains power or dimmer controlled
feeds for spotlights. Intercom cables should cross high
energy cables at an angle of 90º only. Intercom cables
should never be in the same trunks as energy cables.
Place power supply in a central position
In case of a system powered by a separate power
supply: In order to diminish power losses, place the
power supply as close as possible to where most
power consumption occurs, in other words most user
stations are placed.
ASL powered units to a 'clean' mains outlet
Master stations or power supplies should be
connected to the mains outlet with a clean earth. Other
(audio) equipment may be connected to this outlet, but
avoid using an outlet which also powers dimmer
controlled lighting systems.

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User Manual PS 230 / October 2013 © ASL Intercom BV
10.0 EARTHING CONCEPT
11.0 SYSTEM CONFIGURATION