Studio Technologies 2A 2015 - Manual (Page 9)

Model 2A User Guide Issue 2, March 2015
Studio Technologies, Inc. Page 9
switches, allowing the internal microphone
to interrupt IFB channel 1, channel 2, or
both channels 1 and 2.
Monitor Output
The Model 2A contains a simple but excel-
lent monitor output section. At the core is
a 4 watt high-performance audio amplifier
designed to drive an 8 ohm (or greater)
loudspeaker. (The speaker is optional
and is provided as part of an installation.)
Associated with the monitor output are a
3-position source select switch and a level
control. The switch selects whether IFB
channel 1 or IFB channel 2 will be moni-
tored, as well as having an off position. A
click-free circuit mutes the monitor output
whenever the internal microphone or a
Model 22 or Model 24 Access Station is
interrupting either IFB channel.
Model 22 Access Station
The Model 22 Access Station and related
accessories (all purchased separately)
provides the capability for adding up to
four additional interrupt locations. Model 22
units are intended to be installed at posi-
tions convenient to producers, directors, or
other personnel who need to “cue” talent
and related personnel. The unit consists
of a metal chassis containing two lighted
pushbutton switches, unbalanced micro-
phone and balanced line inputs, and status
and control circuitry.
mode is telephone interface 2’s auto an-
swer function. An LED associated with
each telephone interface displays when
the standard audio mode is selected.
Voice Operated (VOX) Interrupt
The Model 2A contains circuitry to allow
an audio signal to serve as both an inter-
rupt audio source and a control signal.
This eliminates the need for a separate
push-to-talk button or contact closure. The
VOX feature allows an audio signal from
a remote source, such as a 2-way radio
or telephone line, to serve as the interrupt
source. The VOX function was optimized
for detecting audio signals in the voice
band. As voice detection is not a trivial
task, great care was taken when designing
the circuitry to support this function.
Three signals can serve as the audio
source for the VOX interrupt function:
receive audio from telephone interface 1,
receive audio from telephone interface 2,
or the auxiliary audio input. The auxiliary
audio input is a separate line-level audio
input that is only associated with the VOX
interrupt function. A 3-position switch se-
lects which source will be used. A second
3-position switch is used to select which
IFB channel is to respond to the VOX inter-
rupt function. The VOX interrupt function
can be assigned to only one IFB channel
at a time or it can be disabled. Each IFB
channel contains an LED indicator light to
display when a VOX (voice-activated) inter-
rupt is taking place.
Internal Interrupt Microphone
Contained behind the Model 2A’s front
panel is an internal interrupt microphone.
Associated with the microphone are two
Figure 2. Model 22 Access Station Front View