Studio Technologies 45DR - Manual (Page 11)

Model 45DR User Guide Issue 2, January 2015
Studio Technologies, Inc. Page 11
unless it can automatically “fall back” to
100BASE-TX operation. An Ethernet con-
nection that supports Power-over-Ethernet
(PoE) is preferred as it will provide operating
power for the Model 45DR. To support PoE
switch (PSE) power management the Model
45DR will enumerate itself as a PoE class
3 device. If PoE is not available an external
12 volt DC power source can be connected.
This will be discussed later in this section of
the guide.
The 100BASE-TX Ethernet connection is
made by way of a Neutrik etherCON pro-
tected RJ45 connector that is located on the
back panel of the Model 45DR. This allows
connection by way of a cable-mounted
etherCON plug or a standard RJ45 plug.
The Model 45DR’s Ethernet interface sup-
ports auto MDI/MDI-X so that most cabling
implementations will be correctly supported.
External 12 Volt DC Input
An external source of 12 volts DC can be
connected to the Model 45DR by way of a
4-pin male XLR connector which is located
on the back panel. While the requirement
for the external source is to be nominally
12 volts, correct operation will take place
over a 10 to 18 volt range. The Model 45DR
requires 1.0 amperes maximum for cor-
rect operation. The DC source should be
terminated to a 4-pin female XLR connector
with pin 1 negative (–) and pin 4 positive
(+). Purchased as an option, the PS-DC-02
power supply is available from Studio Tech-
nologies. Its AC mains input allows connec-
tion to 100-240 volts, 50/60 Hz and its
12 volt DC, 1.5 amperes maximum output
is terminated on a 4-pin female connector.
As previously discussed in this guide, an
Ethernet connection that provides Power-
over-Ethernet (PoE) can serve as the Model
45DR’s power source. Alternately, an exter-
nal 12 volt DC source can be connected.
For redundancy, both PoE and the external
12 volt DC source can be connected at
the same time. If both PoE and an external
12 volt DC source are connected, power
will be drawn only from the PoE supply. If
the PoE source becomes inoperative the
12 volt DC source will provide the Model
45DR’s power with no interruption in opera-
tion. (Of course, if both PoE and Ethernet
data support are lost that is a very different
situation!)
Party-Line Intercom
Connections
The Model 45DR’s party-line intercom inter-
face is designed to function in two distinct
ways. It can be connected to a “powered”
broadcast-standard 2-channel party-line
intercom circuit or directly to party-line in-
tercom user devices. A 2-channel party-line
intercom circuit, such as associated with
TW-series equipment from RTS, has DC
power and two audio channels on a 3-pin
XLR connector. Associated connectors are
wired such that common is on pin 1 and 28
to 32 volts DC is on pin 2. Channel 1 audio
is superimposed on the DC present on pin
2 while channel 2 audio is present on pin 3.
Two impedance-generating networks pro-
vide a 200 ohm audio load from pin 2 to pin
1 and from pin 3 to pin 1. When the Model
45DR’s party-line interface is connected
to an existing intercom circuit it acts, from
an audio standpoint, as a standard user
device. It doesn’t draw (nor supply) any
DC power.
The Model 45DR’s party-line interface can
also serve to create a “mini” 2-channel
intercom circuit. It provides a 29 volt DC
intercom power source and two 200 ohm