Audio Developments AD144 - Manual (Page 40)

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This section should be read in conjunction with Pt 3 of the BLOCK DIAGRAM together
with the following diagrams.
The comprehensive communications module must be fitted in the last position of the
mixer frame. This module enables aural contact between the sound-operator and
three outstations together with the routeing of signals from the mixer for monitoring at
the outstations - boom-man, director, producer etc. The module also has facilities for
injecting marker tone onto the mix busses and for the remote start of a tape machine.
All connections to and from the communications module appear on a 25-way
‘D’ connector which is to be found on the connector panel.
Communications 1 output is the most flexible of the three outputs - the signal
appearing in unbalanced, stereo form on pins (10) L and (11) R of the ‘D’ connector
(see following table). SW (1) routes the stereo output from A & B busses to COMM 1
output and, similarly, SW (2) routes the stereo output from C & D busses. Switches
(3) to (6) route the mono outputs from auxiliaries 1 to 4 to COMM 1 left and right. Any
of these signals may be mixed by appropriate switch selection. Potentiometer (20)
controls the level of signal sent to outstation 1.
Should A/B and/or C/D outputs be in the M-S domain, they may be matrixed into
the L-R domain by DEC (7) - selection being indicated by an LED.
Overriding the above selection of signals to COMM1 is a mono mix of the signals from
input modules that have MON selected. This facility will allow the boom-operator to
audition the boom mic. The signal is routed via CH SEL (8).
An internal microphone (27) with a preset level control (26) allows the sound-operator
to speak to each or all outstations - COMM 1 (19), COMM 2 (21), COMM 3 (24).
An external balanced microphone - pins (13) and (12) on the ‘D’ connector - may be
routed to the three outstations by the same switches - (19), (21) and (24) - that route
the internal microphone. Selection between internal and external microphone is made
by RETURN to COMMS (25). The level of this talkback signal is adjusted by preset
RETURN LEVEL (11). In the centre of the module’s main printed circuit board is a
dual DIL switch that enables a balanced, line-level source to drive the talkback path.
[The signal from this path is routed - under logic control - to the PFL buss.] A PFL
control line will be taken from pin (17) of the ‘D’ connector to the external microphone
position: connecting this pin to chassis ground - pin (1) - will activate the logic and
enable talkback to the sound-operator.
On the module’s sub-board is a dual DIL switch that allows COMM 1 to receive split
monitoring, ie when either the internal or external microphone is in use, its signal will
appear only on COMM 1 left whilst the signal selected on switches (1) to (6) remains
on COMM 1 right. Please note that the module is set, at the factory, for split
monitoring.