Manual

Issue 3, March 2016 Model 45DC User Guide
Page 8 Studio Technologies, Inc.
throughout, providing low-distortion, low-
noise, and high headroom. Using passive
and active filters the frequency response
of the audio channels is limited to nomi-
nally 100 Hz to 8 kHz. This range was
selected to provide excellent performance
for human speech while maximizing the
ability of the hybrid circuits to create sub-
stantial “nulls.”
Audio Meters
The Model 45DC contains two sets of
5-segment LED level meters. Each set of
two meters displays the level of the signals
being sent to and received from a party-
line interface channel. At the time of instal-
lation and setup the meters are invaluable
in helping to confirm correct operation.
During normal operation the meters offer
rapid confirmation of audio signals flowing
in to and out of the unit. Additional LED
indicators are also provided on the front
panel, offering a status indication of the
party-line DC power sources, party-line
activity status, and the auto null functions.
Two other LEDs offer a direct indication
of which source is powering the Model
45DC.
Call Light Support
Typical single-channel party-line intercom
circuits provide a call light function by
way of a DC voltage applied to the audio
path. The Model 45DC can detect call light
activity, convert it to a 20 kHz audio tone,
and transport the tone over the Dante
audio path. A Model 45DC unit at the “far
end” will detect the tone and re-gener-
ate the call signal as a DC voltage on the
audio path. This allows full “end-to-end”
call light support between two or more
Model 45DC units. It also allows a Model
45DC to send and receive call light status
with an interconnected Model 45DR Dante
to 2-Channel Party-Line Intercom Interface.
The Model 45DR is typically used with the
RTS TW-series of party-line user beltpacks
including the popular BP-325.
Ethernet Data, PoE, and DC
Power Source
The Model 45DC connects to a data net-
work using a standard 100 Mb/s twisted-
pair Ethernet interface. The physical
interconnection is made by way of a
Neutrik® etherCON RJ45 connector. While
compatible with standard RJ45 plugs,
etherCON allows a ruggedized, locking
interconnection for harsh or high-reliability
environments. The Model 45DC’s operat-
ing power can be provided by way of the
Ethernet interface using the Power-over-
Ethernet (PoE) standard. This allows fast
and efficient interconnection with the asso-
ciated data network. To support PoE power
management, the Model 45DC’s PoE inter-
face reports to the power sourcing equip-
ment (PSE) that it is a class 3 (mid power)
device. The unit can also be powered
using an external source of 12 volts DC.
For redundancy, both power sources can
be connected simultaneously. An internal
switch-mode power supply ensures that all
Model 45DC features, including party-line
intercom circuit power, are available when
the unit is powered by either source. Four
LEDs on the back panel display the status
of the network connection, Dante interface,
and PoE power source.
Simple Installation
The Model 45DC uses standard connec-
tors to allow fast and convenient intercon-
nections. An Ethernet signal is connected