Manual

Issue 2, October 2018 Model 205 User Guide
Page 12 Studio Technologies, Inc.
MODEL 205
ANNOUNCER’S CONSOLE
the output is identical to the signal that’s
connected to the microphone input but with
a solid-state muting circuit in series with
the interconnection. When the Model 205’s
Dante main output channel is active the
microphone signal will also pass through to
the Model 205’s microphone output connec-
tor. Whenever the Dante main output chan-
nel is muted the microphone signal does
not pass through to the microphone output
connector; it is muted in an essentially
click-free manner. Refer to Appendix A for a
block diagram of the microphone input and
microphone output circuitry.
The microphone output can be connected
to balanced (differential) analog micro-
phone-level inputs on a variety of devices.
This includes microphone input connec-
tions on remote I/O interfaces associated
with a networked audio console. An ex-
ample of such an interface would be the
Calrec® Hydra2®. The mic inputs on these
devices typically offer microphone power,
high-quality amplification, and conversion
to the digital domain. The output signals of
the interface’s pre-amp channels are trans-
ported to the main electronics or console
surface using a fiber optic interface. In this
type of application the Model 205’s Dante
main output channel would not be used or
would only be used as a backup path.
No preamplifier or other active circuitry
impacts the path from the Model 205’s
microphone input connector to the Model
205’s microphone output connector. But the
signal does pass through a 200 ohm resis-
tor in each “leg” (pin 2 and pin 3) along with
connecting to a solid-state relay contact.
The result is that the source impedance of
a connected microphone will be 400 ohms
greater when presented to the microphone
output connector. This will slightly raise the
theoretical noise floor of the microphone
signal vis-à-vis a directly connected mi-
crophone signal but shouldn’t impact any
real-world applications.
Remote Control Inputs
Provision has been made to allow exter-
nal switches or contact closures to mimic
operation of the pushbutton switches
(main, talkback 1, and talkback 2). The
exact functioning of the two remote control
inputs is determined by configuration set-
tings, details of which are discussed later
in this guide. A 3.5 mm 3-conductor jack
is located on the Model 205’s back panel
and provides access to the two remote
control inputs. The input circuitry is “active
low,” with 3.4 k ohm resistors connected
to +3.3 volts DC to act as input “pull ups.”
(In addition, a combination of resistors and
capacitors provide ESD protection, mini-
mizing the chance of damage due to static
discharge or other extraneous signals.) A
current flow of less than one milliampere
is required for a remote control input to be
recognized as active.
Prepare the interconnecting cable and
associated 3.5 mm 3-conductor plug to
reflect that the tip lead is used by remote
control input 1, the ring lead by remote
control input 2, and the sleeve lead is the
connection to common.
Dante Configuration
For audio to pass to and from the Model
205 requires that several Dante-related
parameters be configured. These configu-
ration settings will be stored in non-volatile
memory within the Model 205’s circuitry.
Configuration will typically be done with
the Dante Controller software application
which is available for download free of
charge at www.audinate.com. Versions of
Dante Controller are available to support
Windows and OS X® operating systems.