Studio Technologies 212 2013 - Manual (Page 28)

Issue 5, May 2013 Model 212 User Guide
Page 28 Studio Technologies, Inc.
back panel. It’s recommended that, when
viewed from the back, the EtherCon kit
be mounted on the left side with the metal
locking tab facing to the left.
Three jumper cable assemblies, provided
with the EtherCon kit, are used to link the
Model 212 with the appropriate pairs on
the EtherCon connector. The Model 212’s
AES3 output is accessible on 3-pin header
P8 and should be connected to 3-pin
header P14 on the EtherCon kit’s printed
circuit board. The Model 212’s AES3 input
is accessible on header P9 and should be
connected to header P15 on the EtherCon
kit’s printed circuit board. The Model 212’s
power input is accessible using header P3
and should be connected to header P13
on the EtherCon kit’s printed circuit board.
Once this has been completed standard
computer-style patch cables can be used
to link the Model 212 with a port on the
Model 44 Interface. These cables, often
called “CAT5” patch cables, are “straight
through” and organize their four twisted
pairs as pins 1 and 2, pins 3 and 6, pins 4
and 5, and pins 7 and 8. For reference the
EtherCon Connector Card Kit implements
this interconnection scheme: pins 1 and 2
carry digital audio to the Model 44, pins 3
and 6 bring digital audio from the Model
44 to the Model 212, and pins 7 and 8
bring 24 volt DC power from the Model 44
to the Model 212. The power is polarity
sensitive with positive on pin 7 and nega-
tive on pin 8.
Phantom Power
The Model 212 provides a 48 volt nominal
source of “phantom power” to support
condenser microphones. It’s designed to
meet the P48 requirements as specified
in the IEC 61938 standard. The required
circuitry is very simple: 6.85 k ohm resis-
tors provide a path from a 45 volt source
to pins 2 and 3 of the microphone input
connector. The resistors and the power
source work together to meet the require-
ment of 48 ±4 volts, up to a maximum
current of 10 milliamperes.
LED Colors
As previously described, two LED indica-
tors are associated with the main output
and are located directly above the main
output pushbutton switch. The red LED,
located on the left, is lit whenever the
main output is muted. The green LED,
located on the right, is lit whenever the
main output is active. The thought pro-
cess behind the color choices was that
red would relate to the main output being
muted (“stop”) while green would relate
to the main output being active (“go”). It’s
possible that these color choices may not
meet the needs of all users and applica-
tions. For example, it’s reported that one
European broadcaster typically uses these
two colors in the opposite fashion. Their
choice is to have the red LED lit whenever
the main output is active, warning the tal-
ent that they are “on-air.” The green LED
is lit whenever the main output is muted,
indicating to the talent that it’s “safe” to
say whatever they wish, about whomever
they wish to say it about!
For consistency, the LED associated with
the talkback button was selected to be
green. This lights whenever talkback is
active. It’s possible that some applications
may benefit from revising this LED color
too. While red is certainly one possible
choice, other colors are also a possibility,
including amber, orange, or blue—these
days there are lots of choices available.