Clear-com SB-704 Four Channel Switchboard Main
Station
Clear-com SB-704 is a 2RU four-channel switchboard
main station with programmable front
panel buttons, individual channel
short-circuit protection, individual channel volume control, a
switchboard matrix, and a regulated fail-safe power supply. The SB-704
supports up to 55
beltpacks or 10 speaker stations, or 12 headset
stations. The 10 x 4 assignment switching
matrix allows up to 10
different groups of stations to be assigned to any one of the four channels.
Audio Sources and Monitoring
.The SB-704 accepts five separate program audio
sources: four line-level balances inputs and
one assignable line-level
input. The assignable program input accepts a balanced signal and is
designed for monitoring external audio. The four balanced program inputs can
be used to create individual program feeds on the intercom channels. The
SB-704 can monitor intercom activity on one or all four channels with
individual volume level controls. Monitoring intercom activity is possible
through a headset.
Talk Selection
The SB-704 has mic
pre-amps with limiters and speech-shaping circuits. An individual electronic
momentary/latching Talk button is available for each channel. Illuminated
dual-action Talk buttons light an LED dimly when latched: blue-color while
in standby, amber-color when latched. The latching feature can be disabled.
The channels can be accessed separately or simultaneously without tying them
together. A selector switch toggles between the headset or microphone. The
Talk buttons can also be controlled with a footswitch.
Call Signaling
The SB-704 has
individual Call buttons with visual call signaling for each channel on the
partyline. The visual signal will flash brightly and will emit an audible
signal if the remote station operator holds the Call button for more than 2
seconds. The call signaling feature can be programmed to the Talk buttons.
Remote Mic Kill (RMK)
The SB-704 has a global
Remote Mic Kill button that will turn on the microphone talk circuits of all
beltpacks on the system, eliminating extraneous noise from the open headset
microphones.
Program Input
The SB-704 accepts a
line-level external program input for monitoring in the headset and/or
mixing with intercom audio on up to three of the four channels. When
Interrupt is selected, the program signal is interrupted when the Talk
button is pressed.
Configuration Panel
The SB-704 has a
removable front panel for easy access to the station’s configuration
switches and trim pots. Clearly labeled and easy to adjust, these controls
allow the SB-704 to be configured quickly. When configuration is complete,
the front panel can be reattached so it
shows only the needed controls.
Power
The SB-702 has a visual
indication of power supply conditions. In the event of a short circuit or
current overload on a channel, that channel will shut down while the other
one continues to operate. As soon as the fault condition is removed, the
auto-reset circuitry will restore power to that channel, even under
full-load conditions.
