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User Manual PS 279 / August 2016 © ASL Intercom BV
2.0
GENERAL DESCRIPTION PS 279
The PS 279
(19”/1RU) is designed to be a dual
channel master unit in an ASL intercom system.
Each channel has a Volume (listen level) control,
a TALK and a CALL button with LED indicators
and a side tone trimmer.
To connect the unit to its remote stations, use
microphone cable with 2 wires and 1 shield
The built-in power supply can safely drive up to 20
Pro Series beltpacks or 10 remote 2-ch speaker
stations operating at full power. The power supply
is protected against wiring mistakes (reverse
power), short circuit or excessive thermal
condition. Should one of these conditions occur,
the unit shuts down. Once the fault condition has
been removed, the unit resets automatically and
full power is restored.
In case the number of user stations exceeds the
capacity of the PS 279 power supply, the PS 285
booster power supply can be used.
Should the PS 279 be connected to another
Intercom system, the ‘System link’ connector at
the rear of the unit has to be used. This to avoid
impedance problems.
Special attention has been paid to the intelligibility
of speech. By applying low noise/high speed op-
amps, a speech presence filter and a proprietary
headphone amplifier, communication is very
comfortable even in environments with a high
background noise level.
The unique CALL system provides both a flashing
red LED and a very distinctive and characteristic
sound signal. Only a short push of the CALL
button will make the LED flash. The Call sound
signal (buzzer) is activated by holding the button
for two seconds. In case the sound signal is
undesirable, all buzzers can be muted with the “All
buzzers on/off” button.
Fully electronic switching allows for
“soft”
microphone on switching (latched or momentary)
and remote Mic Mute facility. All microphones of
stations connected to the PS 279 can be muted by
pushing a single button on the front panel.
An AUX input at the rear panel allows inserting
external audio signals at line level. The Aux signal
can be routed to intercom line A and/or B, or
directly to the local headset.
As an option, an XLR-6 headset connector can be
fitted for binaural user of the headset cans
(channel A + AUX signal on the left headset can
and channel B + AUX signal on the right headset
can.
Changing the position of internal jumpers makes it
possible to route channel A + B to the left can and
the AUX signal to the right can.
3.0
MAINS POWER & SAFETY EARTH
WARNING: This appliance must be earthed
The PS 279 may be connected to a mains power
outlet of 100 - 240 V AC (50 - 60 Hz), 100 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: safety ground
Blue: neutral Brown: live
In case the colors of the wires in the mains lead
do not correspond with the colored markings of
the terminals in your plug, proceed as follows:
The wire that is colored green-and-yellow
must be connected to the terminal in the
plug, which is marked with the le
tter “E”, or
by the ground symbol, or is colored green.
The wire that is colored blue must be
connected to the terminal that is marked
with the letter “N” or colored black.
The wire that is colored brown must be
connected to the terminal marked with the
le
tter “L” or is colored red.
For personal safety and for proper functioning of
the PS 279 and connected stations the green-and-
yellow wire of the mains cord must always be
connected to the electrical installation safety earth
or ground. This wire is internally connected to all
exposed metal surfaces. Any rack framework into
which this unit might be mounted shall be
connected to the same grounding circuit.
The PS 279 employs professionally designed
input and output circuits which do not require the
disconnection the safety earth to avoid hum loops.
Powering up procedure:
Make sure the power switch is OFF.
Connect the power cord to the unit
Plug the other end of the power cord into a
PROPERLY GROUNDED
outlet.
Turn on the power with the red button.
The red overload LED will light up for
about 3 seconds, then extinguishes and
the green power LED will switch on,
indicating the station is active.
