MODEL:
JUSTTALK
DUPLEX TALK THROUGH COMMUNICATOR
INSTALLATION DETAILS / HOOK-UP DIAGRAM
SPEAKER
SPEAKER
MIC
-
+
-
+
MIC
SPEAKER
-
+
SPEAKER
+
-
MIC
P1
P2
P7
P6
U3
R12
R13
R19
R20
+MIC-
-MIC+
LIN
LOUT
GND
+12V
+SPK
-
-SPK+
NULL
VOL
P3
P4
P5
MUTE
GND
HC-0825 RE
V. A
DIFFERENTIAL A
MPLIFIER
FL
O
FHI
P1
P2
P7
P6
U3
R12
R13
R19
R20
+MIC-
-MIC+
LIN
LOUT
GND
+12V
+SPK
-
-SPK+
NULL
VOL
P3
P4
P5
MUTE
GND
HC-0825 RE
V. A
DIFFERENTIAL A
MPLIFIER
FL
O
FHI
MIC
+ TO 12VDC POWER SUPPLY
- NOTE (-) SHOULD BE COMMON TO EARTH
ST
AFF
TALK A
MP
ST
AFF LISTEN A
MP
FIELD
TERMENATIONS
#22 OR LARGER
NOTCH
1
NOTCH
2
VOL
MIC
BALANCE
NOTCH
3
NOTCH
4
VOL
MIC
BALANCE
CLIENT
ST
AFF
INSTALL
IN
CONDUIT
OUTLET
BOX
INSTALL
IN
CONDUIT
OUTLET
BOX
2
1
3
4
5
6
2
1
3
4
5
6
2
1
ADJUSTING JUSTTALK UNITS – CLOSE DOORS AND WINDOWS -
Units are shipped with factory operating settings and should require only minor adjustments. If feedback does occur, go to steps #1 and #5, use
small increment steps of tuning volume and notch filters.
The adjustments require a small “flat blade” screwdriver –
Remove 8 set screws for access to internal adjustment pots – the right side 4 adjustments are for client side station.
Note: tapping housing near mike with a finger will aid in adjusting by providing a reference level. If adjustment steps #3 and #5 does not clear
the feedback, the following is the full re-calibration procedure.
Be consistent - be patient.
Set external volume knobs - fully clockwise (max volume setting) upper knob is client listen
Set internal volume pots - mid-way
Set notch filter pots -mid-way
Initially retain factory internal mike pot settings (see step #2)
Power up (ring LED illuminates)
If feedback occurs -
1. Reduce volume – adjust volume pots clockwise until feedback is eliminated – alternate between the two amplifiers so both are
approximately at the same volume level –
a. Adjust to highest volume -
2. Adjust mike pot balance on each unit – alternate between the two amplifiers so both are approximately at the same volume level –
a. Adjust to highest volume –
Alternate adjustments between steps #3 and #4 -
3. Increase volume – adjust internal volume pots counterclockwise until feedback re-occurs. Try to keep both amplifiers at same volume
level. When feedback is just starting, go the step #4.
4. Adjust notch filter pots until the feedback frequency is muted – begin with notch pot #4 to match the lowest frequency (where possible).
Continue with step #5.
5. Repeat steps #3 and #4 for each feedback frequency
There are four notch filters (two on each amplifier) – each one will mute a different feedback frequency.
Making small adjustments between testing will be to your benefit –
Units are calibrated for maximum volume. Adjust external volume knobs for desired operating volume.
Replace 8 set screws –
