Datasheet

Break the Feedback Loop
Acoustic feedback is the phenomenon that
causes the annoying, high-pitched squeal
that sometimes occurs in paging systems.
Making a page in especially loud paging
areas can be almost impossible because of
acoustic feedback. Numerous ways of
treat-
ing this problem, from re-aiming speakers
to
using special telephone mouthpieces,
have
been used with varying levels of success.
The DFT120 solves the problem of annoying
feedback squeals once and for all by
breaking the feedback loop that exists be-
tween the speakers and the telephone re-
ceiver. Every page is first digitally recorded
and stored in memory. When the paging
telephone is hung up, the DFT120 plays
the recording back over the paging system,
with no possibility of feedback.
Page Stacking
It is important to be able to record one page
announcement after another without delay
because paging announcements happen ran-
domly. The DFT120 is designed for high traf-
fic paging because of its ability to “stack” page
announcements. New announcements can
be recorded while an existing one is being
played. In fact, the DFT120 can store up to 8
announcements at one time. Two separate
banks of memory “ping-pong” between
recording and playback to provide unim-
peded access to the paging system.
Accessories
Digital Feedback
Terminator
DFT120
Product Features:
• High sampling rate for excellent playback
quality
• Able to record a message while another
is played
• Stacks up to 16 messages for playback
• 240 seconds of total audio memory
• Automatic or externally controlled unit
operation for recording, play, and stop
• Activates recording by loop start trunk,
4-wire dry loop, audio trigger, or DTMF
• Digital recording and playback of pages,
60-second maximum message length
• Adjustable delay times between messages
• Message repeat, abort, stop, and
pre-page tone option
• 8- or 600-ohm output impedances
• Zone control DTMF tones stripped from
message and regenerated
• Easy installation and low maintenance
• Volume control
• Wall mountable
• Adapter included
TAMB2
Telephone
Access Module
Power Product
Requirements Dimensions Weight
12V Power Supply (included) 10" W x 6-1/2" H x 1-1/2" D 2 lb.
The DFT120 eliminates the acoustical feedback
loop created by the telephone handset and the
paging speaker while providing high-capacity,
high-quality recording and playback of audio pages.
Product Features:
•4 types of tones: steady, pulsed alarm, slow whoop, and chime
•Tones triggered by external contact closure
(momentary or long duration)
•Choice of continuous generation of tones or two-burst
operation (except for steady tone)
•External audio signal can pass through the TG4C
and is suppressed during tone generation
•Adjustable tone level & pitch
•600-ohm output
•Tone generation reset available
Accessories
Power Product
Requirements Dimensions Weight
2 lb.
Wide power
supply range, 12V
to 48V DC @ 30
mA (power supply
not included)
6-3/4" W
x
5-3/4” H
x
2" D
PRS40C
12V DC
Power
Supply
WMT1A
Matching
Transformer
TG4C
The TG4C is designed to produce four different types
of tones for use as alarm or announcement signals
in paging systems. An audio signal can be routed
through the TG4C to allow easy installation in paging
systems. During generation of the tones, the routed
audio will be suppressed.
Easy To Use
The TG4C is designed to provide a wide
range of alarm/warning tones for non-
critical applications. An external contactclo-
sure triggers the generator. A momentary
contact will produce two plays of the selected
tone, while a continuous closure will regen-
erate the tone until it is removed.
Input Sharing and Priority
A unique feature of the TG4C is the unit’s
ability to pass through a signal and then sup-
press it during tone generation. This allows
the TG4C to be installed in any paging sys-
tem without losing an input. This feature also
gives the tones priority over the signal it sup-
presses, a valuable feature in most
alarm/warning situations.
www.bogen.com
53
PAGING ELECTRONICS
DIGITAL FEEDBACK ELIMINATION
TONE GENERATOR
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