Service manual

USING THE SPEAKER
When
the
KB-112 is
set up
for the
activates
the Call
circuit.
That
Normal
mode or the
Remote
Listen
Station
must be
connected
to the
mode, its
speaker stays "on"
so the same
channel used by the KB-112.
operator
can monitor
activity
on
the intercom
channel.
When
the
When the
KB-112 is set
up for
the
operator
turns
on the mic
(or if
Remote.Listen-Page
mode, the
spea
the
mic is turned
on from a remote
ker
stays off EXCEPT
when another
location), the speaker
automatical-
Station activates
the "Call"
cir-
ly shuts off.
cuil:.
Due to the
nature of
the
reverse
logic,
when
in this
mode
When
the
KB-112 is
set up
for the
the
KB-112 operator
can also
turn
Remote
Page
mode,
the speaker
can
on
the speaker
by
pressing
the
turn
on only when
another
Station
black
"push-to-talk"
button.
USING
THE EXRNAL
PROGRAM INPUT
mixing console,
the output
of a
If
your intercom
is used in
thea-
mini mic-mixer,
the pre-amp
output
trical
or musical
production,
the of
an amp, etc.
KB-112's "Program Input" might be
useful. It
enables you to listen to
Use single-conductor, shielded
ca-
an external
audio source in addi-
ble to input "program" to the
KB-
tion to the
intercom audio.
Simply
112.
Connect the
hot lead
from
feed
an unbalanced,
line-level
sig-
your
source
to terminal
2
on the
nal to the KB-112 terminal
strip. KB-112 terminal strip,
and connect
the
ground
lead
from
your
source
to
This application
works when
the KB- terminal
5.
112 is set up for "Normal," "Remote
Page," or "Remote Listen" mode of
If a balanced input is desired,
operation. The
program audio
is insert
a balancing transformer
completely isolated from
the inter- between the
KB-112's access point
com audio, and is cut off when the and the program source.
KB-112's mic is activated.
The
program
volume
is
adjustable
Connecting The Input
from
the source end; use the
audio
The
program access point
is high-
source's VU meter
reading as
a
impedance, about
500k ohms.
There-
volume control
reference.
Or for
fore it can be driven by an audio local control of the program vol-
device of virtually any impedance; ume, refer to the set-up shown in
it could be
the monitor buss off a
Figure 4, Typical Program Feed.
Figure
4: TYPICAL
PROGRAM
FEED
OdB
3
Line-Level
Output
_
;L4
>
~~~~~GND.
5
PRO GRAM
VOLUME CrONTROL'
10Dk OHMAUDIOTAPER
'Volume Control is optional. If desired, it
6 ma beinlstalledateithertheKB-112end
or the progra source end.