Manual

Model 44D User Guide Issue 3, August 2018
Studio Technologies, Inc. Page 21
GPI/GPO
Whether or not the general-purpose inputs
(GPI) and general-purpose outputs (GPO)
functions are implemented will depend on
the needs of the specific application. If the
appropriate connections are made using
the 9-pin D-subminiature connector either
or both functions can be utilized. No user-
action is required for the functions to be
active. There is no user indication when a
GPI input has been activated. Two front-
panel LEDs will indicate when a signal on
the Dante receiver input has been recog-
nized as a GPO.
A typical application might find two Model
44D units communicating with each other.
For clarity, we’ll call them Unit A and Unit
B. An analog audio signal connected to
input 1 on Unit A will be transported via
Dante to Unit B and then sent out Unit B’s
line output 1. Signals connected to the
line inputs on Unit B will end up on the line
outputs of Unit A. How the GPI and GPO
functions will be similar. Activating GPI 1
on Unit A will result in activation of Unit B’s
GPO 1. This condition will be noted by the
GPO 1 LED lighting on Unit B. Closures
on Unit B’s GPI 1 and GPI 2 will result in
activation of Unit A’s GPO outputs and
associated LEDs.
Advanced applications may use a Model
44D unit to interface analog audio, GPI,
and GPO signals associated with intercom
or broadcast routers with Studio Technolo-
gies’ Model 45DC or Model 45DR inter-
com interfaces. Since the three units (44D,
45DC, and 45DR) all use 20 kHz tones
for signaling direct compatibility between
GPI, GPO, and party-line intercom call-
light functions is possible.
Tone Generator
Switch SW4, located on the back panel, is
used to configure Model 44D’s operating
mode. When selected for the tone gen-
erator mode (SW4 on (up)) normal audio
interface operation will not take place. The
unit’s internal processor will generate two
sine-wave audio signals (tones). The unit
will function in this manner:
• An 18 kHz tone at a nominal level of
+4 dBu will be present on analog line
output channel 1.
• A 20 kHz tone at a nominal level of
+4 dBu will be present on analog line
output channel 2.
• An 18 kHz tone at a level of –20 dBFS
will be present on Dante transmitter
(output) channel 1.
• A 20 kHz tone at a level of –20 dBFS
will be present on Dante transmitter
(output) channel 2.
• The two line output meters on the
Model 44D’s front panel will display
a constant value of 0.
• The Dante transmitter (output) channels
will have names of 18kHz and 20kHz.
• The Dante receiver (input) channels
will have names of Ch1–Inactive and
Ch2–Inactive.
• The two analog line input channels on
the Model 44D’s back panel will not be
active.
• The two Dante receiver (input) channels
will not be active.
• The two line input meters on the Model
44D’s front panel will not light.
• The two GPI functions will not be active.