Studio Technologies 230 2014 - Manual (Page 42)

Issue 9, November 2014 Model 230 User Guide
Page 42 Studio Technologies, Inc.
P10: IFB Input, pin 1 common, pin 2 DC
with channel 1 audio, pin 3 channel 2
audio. Follows back-panel 3-pin female
XLR pin assignment.
P11: Intercom Interface, pin 1 common,
pin 2 DC with channel 1 audio, pin 3
channel 2 audio. Follows back-panel 3-pin
female XLR pin assignment.
Additional functions can be accessed
using these 3-position headers:
P13: Talkback-to-Intercom Channel 2
“Dry” Output, pin 1 common, pin 2 audio,
pin 3 not used.
P14: Talkback-to-Intercom Channel 1
“Dry” Output, pin 1 common, pin 2 audio,
pin 3 not used.
P15: Auxiliary Relay Contact B, pin 1
normally closed, pin 2 common, pin 3
normally open.
P16: Auxiliary Relay Contact A, pin 1
normally closed, pin 2 common, pin 3
normally open.
P17: Internal Power Supply Rails, pin 1
common, pin 2 +12 Vdc, pin 3 –12 Vdc.
P18: Remote Switch Connections, pin 1
common, pin 2 main out button, pin 3
aux (currently not supported in software).
P19: Remote Switch Connections,
pin 1 common, pin 2 talkback button 1,
pin 3 talkback button 2.
P23: Internal Power Supply Rails, pin 1
common, pin 2 +12 Vdc, pin 3 –12 Vdc.
Remote Control Connections
Provision has been made on the Model
230’s printed circuit board assembly to
allow external switches or contact clo-
sures to control the main out and talkback
button functions. Two 3-position headers
provide access to the circuitry associated
with the functions.
P18: Remote Switch Connections, pin 1
is connected to the common point of the
Model 230’s circuitry. Pin 2 is connected
to the circuitry associated with the main
out pushbutton. Pin 3 is connected to
the circuitry associated with the auxiliary
pushbutton input. (This function is not
currently supported in software.)
P19: Remote Switch Connections, pin 1
is connected to the common point of the
Model 230’s circuitry. Pin 2 is connected
to the circuitry associated with the talk-
back 1 button. Pin 3 is connected to the
circuitry associated with the talkback 2
button.
The input circuitry is “active low,” with a
10 k ohm resistor connected to +5 volts
acting as a pull up. A combination of resis-
tors and capacitors provide ESD protec-
tion. A qualified technician can use these
inputs for special applications. Contact the
factory for additional details.
Compressor Circuit
In this section some general information
about the Model 230’s compressor
circuit will be provided. As previously
discussed, the output of the microphone
preamplifier circuit is connected to a
studio-quality compressor circuit. The
output of the compressor is used by the
talkback functions and, if the unit has
been modified, the main output. (In most
cases the main output will utilize the signal
coming directly out of the microphone
preamplifier.) The gain element in the
compressor circuit is a laser-trimmed
voltage-controlled-amplifier integrated
circuit. It provides accurate, low-noise,
low-distortion performance. The threshold
of the compressor circuit is 2 dB above