Manual

Model 45DC User Guide Issue 3, March 2016
Studio Technologies, Inc. Page 11
(PoE) is preferred as it will provide operat-
ing power for the Model 45DC. To support
PoE switch (PSE) power management the
Model 45DC 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 in the
next section of this 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 45DC. This
allows connection by way of a cable-
mounted etherCON plug or a standard
RJ45 plug. The Model 45DC’s Ethernet
interface supports auto MDI/MDI-X so
that most cabling implementations will
be directly supported.
External 12 Volt DC Input
An external source of 12 volts DC can be
connected to the Model 45DC 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 45DC
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
45DC’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
45DC’s power with no interruption in oper-
ation. (Of course, if both PoE and Ethernet
data support are lost that is a very different
situation!)
Party-Line Intercom
Connections
The Model 45DC’s party-line intercom inter-
face is designed to function in two distinct
ways. It can be connected to one or two
“powered” broadcast-standard 2-channel
party-line intercom circuits or directly to
one or two sets of party-line intercom user
devices. A single-channel party-line inter-
com circuit, such as frequently associated
with equipment from Clear-Com, has DC
power and one audio channel on a 3-pin
XLR connector. The connector is wired
such that common is on pin 1, 22 to 30
volts DC is on pin 2, and audio is on pin 3.
An impedance-generating network pro-
vides a 200 ohm audio load from pin 3 to
pin 1. When the Model 45DC’s party-line in-
terfaces are connected to existing intercom
circuits they act, from an audio standpoint,
as standard user devices. They don’t draw
(nor supply) any DC power.
The Model 45DC’s two party-line interfaces
can serve to create two “mini” intercom
circuits. They each provide a 28 volt DC
intercom power source and a 200 ohm
impedance generator, allowing a limited
number of single-channel intercom user
devices to be directly connected. The Mod-
el 45DC’s two internal 28 volt DC power