Studio Technologies 212 2013 - Manual (Page 23)

Model 212 User Guide Issue 5, May 2013
Studio Technologies, Inc. Page 23
Incorrectly setting the digital input source
will probably prove to be the most com-
mon cause of incorrect Model 212 opera-
tion. Carefully reviewing the connected
signals and then selecting the appropriate
interface will lead to successful operation.
Relay Mode
Switches SW3-9 and SW3-10 are used
to configure the operating mode of the
auxiliary relay.
Figure 15. Relay mode settings
75 ohm unbalanced (AES3id) and 110
ohm balanced (AES3) digital audio sig-
nals. However, that was revised under
a newer revision of the AES3 standard
which now covers both balanced and
unbalanced implementations.
The bidirectional digital interface is a
special type of 75 ohm unbalanced signal
that carries two channels of digital audio
in each direction. To clarify, over a single
unbalanced cable two channels of digital
audio are sent in one direction and two
channels of digital audio are sent in the
other. The bidirectional digital interface
uses a BNC connector which is located
on the Model 212’s back panel. The inter-
face is only appropriate for use in carefully
engineered systems that are compatible
with this type of signal. An example ap-
plication is where a Model 212 is directly
interfaced with a 75 ohm port on a Riedel
digital matrix intercom system.
AES3 input circuitry is located inside the
Model 212’s enclosure and is compatible
with balanced 110 ohm digital audio sig-
nals. This type of signal is typically found
in non-broadcast applications where the
use of twisted pair wiring with a maximum
interconnection length of 100 meters does
not pose a problem. The Model 212 pro-
vides the AES3 input circuitry for installer-
selected applications where the desired
connector is mounted into one of the
spare connector locations on the Model
212’s back panel. Many applications use
standard 3-pin female XLR connectors for
AES3 inputs. However, using other con-
nector types, such as Neutrik EtherCon,
can be a convenient way of transporting
a number of different signals over “CAT5”
or “CAT6” twisted-pair cable.
Three modes are available:
• Relay is disabled: In this mode the relay
is disabled and will never change state.
• Follows main output status: In this mode
the relay will follow the state of the main
output channel. Specifically, the relay
will change state (energize) whenever
the main output channel is active.
• Follows talkback button status: In this
mode the relay will follow the state of the
talkback output channel. Specifically,
the relay will change state (energize)
whenever the talkback output channel
is active.