Sigtronics RES-601 Operating Instructions - Manual

Sigtronics ST-400 / ST-600 STEREOCOM Operating Instructions
Specialists in “SOUND” Management
178 East Arrow Highway, San Dimas, CA 91773 ( 909 ) 305-9399
INTERCOM OPERATION
The intercom portion of the Sigtronics Stereocom ST400 /
ST-600 system is voice actuated with “transmit through the
aircraft radio capability” using your push-to-talk switches.
Three controls are provided on the SPA units:
ON/OFF Switch - Sets the intercom mode of operation.
VOL - Volume Control - Controls the intercom volume. (Does
not affect aircraft radio volume. Set radio volume on radio
as normal.)
SQ - Squelch Control - Allows the setting of VOX operation
of the intercom for variations in background noise levels and
differences in headset microphones.
CAUTION - As is standard practice with all aircraft avionics
equipment, be sure that the aircraft radio master switch is
turned off when you start up the aircraft engine.
1. With aircraft power on, set the MUSIC ON/OFF switch to
“OFF” and the PILOT/ALL switch to “ALL”. Turn the SPA
ON/OFF switch to the “ON” position.
2. Turn the intercom SQuelch control to the maximum
clockwise position. For best system performance set the
intercom VOLume control as low as possible. On most
systems this will be approximately between 1/4 to 1/3
open. Note: the intercom volume control only adjusts the
volume of conversation between the headsets inside
the aircraft. It does not affect the level at which you hear
the aircraft radio(s) or the level of the music. Notice the
intercom is now continually activated (hot mic mode) and
you should be able to talk between headsets.
3. To adjust the Intercom SQuelch for voice activated
operation (VOX), it is helpful to have some background
noise present. Turn intercom SQuelch control all the way
counter-clockwise. Now, without speaking, rotate the
SQuelch control clockwise until you hear the background
noise in your headset. Next, rotate it counter-clockwise
a small amount and wait (approximately 1 second)
until the background noise disappears. Finally, make
small adjustments until your voice triggers the unit at
comfortable speaking levels. This procedure is necessary
because the squelch is a “Fast-on, Slow-off” system.
Once set, the intercom stays silent until someone speaks
in their headset microphone (mic). Then it instantly turns
on and relays the conversation. After about a second of no
conversation, the intercom goes silent again.
Minor readjustment of the SQuelch may be necessary if the
background noise level changes significantly (such as from
taxi to take-off power conditions).
Radio Transmit Mode
When the SPA unit is “ON”, transmitting from both pilot and
co-pilot positions is possible on a one-at-a-time basis. As
normal, the pilot selects the appropriate radio he wishes to
use. When the pilot presses his PTT switch, his headset mic is
automatically routed through the intercom to the radio. Only
his mic will be live. The microphones of the co-pilot and any
passengers, will be muted when the pilot transmits. Similarly,
when the co-pilot transmits, only the co-pilots mic will go
out on the radio. When transmitting, the pilots will hear their
own voice via the aircraft radio sidetone return. (If the radio
does not provide transmit sidetone, then you will not hear
your voice. A minor modification to the SPA unit will enable
it to simulate sidetone. (See the “SPA-400 / SPA-600 Sidetone
Modification” instructions under the “HELPFUL HINTS AND
TECHNICAL INFORMATION” section of the ST-400 / ST600
STEREOCOM INSTALLATION INSTRUCTIONS).
When the SPA is turned “OFF”, only the pilot can transmit
on the aircraft radio(s). Both pilot and co-pilot will hear the
aircraft radio(s). The passengers will also hear the aircraft
radio(s) if the PILOT/ALL switch is in the “ALL” mode. With
the SPA unit “OFF” you will not hear intercom and cannot
talk to the other headsets.
Solo Flights
Since the intercom is not needed during solo flights, it may
be turned “OFF”. The pilot will still hear the aircraft radio(s),
since this circuit is always active, and may transmit to ATC via
his headset and push-to-talk switch. The pilot can also listen
to music (interrupted only by aircraft radio traffic) by turning
“ON” the MUSIC ON/OFF switch.