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2 CM-CU21 Mains Controls & Indicators
Talkback Buttons
The Talkback A and B buttons allow either of the two main commentators’
microphone signals to be redirected to the corresponding Talkback output.
The associated Comm output is muted and the commentators’ signal is
removed from the Mix Outputs. The four return audio inputs Prog, A, B and
C function normally when a Talkback channel is active, allowing full-duplex
communication between the commentator and a third party.
An alternative operating mode allows the Talkback B buttons to act as a
temporary mute control for the Comm1, Comm2 and Talkback A outputs.
The Talkback B buttons are ganged and the status of any active On Air or
Talkback A channels is restored once both of the Talkback B buttons are
returned to the off state. The Talkback B output is not used in this mode.
See Configuration Options on Page 23 for details of how to change these
settings.
These buttons have a momentary action by default; press to activate,
release to deactivate. See Configuration Options on page 25 for details
of how to change the button action. When a Talkback control is active,
the button illuminates green and the corresponding open collector driver
output on the GPIO port is activated.
Headphone Monitor Controls
The two main commentator positions have six sets of headphones
controls which allow them to monitor all of units’ return audio and
active commentator inputs. Each available input has an associated level
adjustment potentiometer and a headphone channel selector switch. Each
potentiometer provides a level adjustment from “full off” to “full on”, and
the headphone channel selector determines which ear the associated
signal is routed to; either the left, the right or to both ears when the switch
is in the centre position. By default, the commentator input signals are
only routed to the headphone monitor controls when the corresponding
On Air control is active. It is possible to route each of these signals to the
headphones permanently, regardless of the state of the corresponding On Air
control. See Configuration Options on Page 24 for details.
The guest position, commentator 3, can be set to accept a line level input, and
an additional option can be configured to prevent this signal from being routed
to the commentator 1 and 2 headphone monitors.
The headphone controls for the third commentator position consist of left
and right level adjustment potentiometers, and a switch to select the routing
for the commentator input signals. With the switch in the left position,
commentator 1 is heard in the left ear and commentator 3 is heard in the right
ear. With the switch in the right position, commentator 2 is heard in the right
ear and commentator 3 is heard in the left ear. When the switch is in the centre
position, commentator 1 is heard in the left ear, commentator 2 is heard in the
right ear and commentator 3’s own signal is heard in both ears.
Commentator 3 Line Input Level Control
When the third commentator input is set to accept a line input, this
potentiometer sets the gain applied to the signal prior to being routed to the
headphone monitor and main output channels. The gain range is -83dB to
+10dB with a maximum input level of +25dBu.
PPM Meter Display
The 21 segment LED PPM meter display indicates the level of the signal on the
mix outputs. The PPM scale conforms to IEC60268-10 11a and a dB scale is also
shown. There are options to set the brightness level of the PPM meter, or it can
be disabled if it is not required. See Configuration Options on Page 26 for
details.
Limit LED
The limit LED illuminates when the adjustable limiter on the mix outputs is
enabled and active. See Rear Panel Controls on Page 20 for details of how to
enable and adjust the limiter. The colour and brightness level of the limit LED
can be changed if required, see Configuration Options on Page 25 for details.
