Q700
14
System Operation and Features
System Operation
Assuming that all active receivers are
enabled, and that there are two separate
active intercom lines, operation of the
Q700 system in the standard
configuration is as follows:
• Incoming audio from the primary
wired intercom channel is always
routed to the MS-700 transmitter
main audio channel.
• Incoming audio from the secondary
wired intercom channel is not
continuously routed.
• Program/IFB audio is continuously
routed to the MS-700 subcarrier
audio channel.
• If no BP-700 beltpacks are
transmitting, all MS-700 receiver
audio outputs are muted.
• The BP-700 continuously sends a
digital control signal when it
transmits.
• The actual digital control signal
transmitted from the beltpack
depends upon whether pushbutton
“A”, “B”, “C” or “D” is depressed.
• Audio routing of the receiver audio
signals in the MS-700 is determined
by the control signals from the
BP-700’s.
• If the beltpack is in the continuous
transmit mode, the audio will be
routed in accordance with the last
control button pushed.
• If a specific beltpack user selects
“A”, the associated receiver audio
will be routed to the MS-700
transmitter main audio channel and
to the primary wired intercom
channel. This is the basic operating
mode.
• If the beltpack user selects “B”, the
receiver audio will be routed to the
MS-700 transmitter main audio
channel and to the secondary wired
intercom channel. It will not be
routed to the primary intercom
channel. At the same time, audio
from the secondary intercom
channel will be routed to the
transmitter main audio channel.
This allows a beltpack user to
communicate on the secondary
intercom channel while still
monitoring the primary channel,
without mixing the two intercom
channels.
• If the beltpack user selects “C”, the
receiver audio will be routed to the
MS-700 transmitter main audio
channel only. It will not be routed
to either the primary or secondary
wired intercom channel. However,
incoming audio from the primary
intercom channel will continue to
be applied to the transmitter main
audio channel. This allows the
wireless beltpack users to have a
private conversation while still
monitoring the primary intercom
channel.
• If the beltpack user selects “D”, the
receiver audio will be routed to the
MS-700 transmitter main audio
channel and to the auxiliary audio
output connector. At the same
time, the auxiliary control relay
contacts will close. Receiver audio
will not be routed to either the
primary or secondary intercom
channel. However, as above,
incoming audio from the primary
intercom channel will continue to
be applied to the transmitter main
audio channel.
• Operation of each beltpack is
independent of each other, so more
than one of the above modes can
exist at the same time. Only in the
case of mode “B”, where the
secondary intercom channel is
applied along with the primary
channel monitoring to the MS-700
transmitter, will the modes interact.
Operational Features
MS-700 Intercom Interfaces
The MS-700 master station will
interface with two intercom lines
simultaneously, as well as accommodate
both four-wire inputs/outputs and
conventional intercom inputs/outputs
for each line at the same time. Standard
Clear-Com, Clear-Com TW and RTS
systems are accommodated via two 3-
pin XLR connectors, while the four-wire
interfaces appear on two adjacent 4-pin
XLR connectors. All intercom interfaces
are fully transformer isolated to reduce
hum and noise.
A pushbutton switch is provided to
allow easy selection of the Clear-Com
and TW/RTS modes. This switch selects
the input connector for intercom line
two (IC1/IC2 or IC2) and adjusts the
interface level to accommodate the
differences between the two types of
lines. The switch does not affect the
four-wire interfaces.
Front panel enable switches are
provided for each of the two intercom
lines, as well as input and output level
adjustment controls. These controls are
for trimming levels, they do not have a
wide adjustment range. A null control is
also provided for each intercom line.
This control allows adjustment of
sidetone level of the lines to
accommodate different cable lengths
and wired intercom system
configurations. It does not directly
affect the four-wire output, but can
introduce unwanted sidetone on the
four-wire output if not adjusted
properly.
To adjust this control, enable the
intercom line and adjust the input and
output level controls as necessary. Have
a BP-700 user activate button "A" and
then speak into their headset
microphone. Enable this beltpack with
the corresponding receiver "on" button.
Monitor the intercom line via the
headset jack on the MS-700 front panel.
Initially adjust the null control for
minimum sidetone level on the intercom
line. Then readjust the control slightly to
increase the sidetone level and give it a
natural sound quality. Try both sides of
the minimum sidetone adjustment
point.
Program Audio Input
The MS-700 accepts a line-level
balanced audio input via a 3-pin XLR
connector. The signal is normally routed
to the second audio channel (subcarrier
channel) of the MS-700 transmitter. The
audio is then available to BP-700 users,
where it can be adjusted by a second
volume control. This capability provides
built-in IFB or program audio capability
in the BP-700, but may be used for
other purposes such as connection to a
remote ENG or production vehicle. The
incoming signal may be monitored and
adjusted from the front panel of the
MS-700, but can only be completely
disabled by disconnecting the source.
Auxiliary Output
The MS-700 also provides a fixed, line-
level balanced audio output on a 3-pin
XLR connector. Audio from one or more
BP-700 beltpacks will be routed to this
connector when the beltpack user
selects pushbutton "D" on the beltpack
control panel. Unless one beltpack user
selects their mode "D", no audio appears
on this output.
There is also an associated contact
closure available on a 9-pin type "D"
connector on the MS-700 rear panel.
This contact closes when a BP-700 user
