TM 11-6625-441-12
SEL switch to INTER.
sidetone should be audible from the headset.
m. Turn the interphone control VOL control to
g. Release interphone test set SIGNAL switch
mid-position.
and KEYING switch; sidetone shall cease.
n. Place the interphone test set SIGNAL switch
h. Rotate interphone control transmit-
to HD MIC and hold. Place the KEYING switch to
interphone selector switch to PVT position.
INTER and hold.
i. Place and hold interphone test set SIGNAL
o. Speak into the microphone. Sidetone should be
switch to HD MIC.
heard in the headset.
j. Speak into the mike; sidetone should be audible
p. Perform the stopping procedure (para 3-6).
from the headset.
k. Release interphone test set SIGNAL switch;
sidetone shall cease.
3-5. Testing Hot Mike and Sidetone Circuits
l. If further testing is not required, perform the
stopping procedure (para 3-6).
a. Perform the preliminary starting procedure
b. Place interphone control transmit-interphone
3-6. Stopping Procedure
selector switch to the INT position.
c. Rotate interphone test set OUTPUT SEL
to OFF.
switch to position R and RECEIVER SEL switch
b. Turn the 28-vdc power supply off and discon-
to the INTER position.
nect the interphone test set power cable from the
d. Position the headset microphone in place on
28-vdc power source.
operator's head.
c. Disconnect the interphone test set test cable
e. Place and hold interphone test set SIGNAL
from the interphone control; roll and store the
switch to HD MIC and KEYING switch to
cables in the cable storage compartment.
INTER.
f. Speak into the mide and slowly rotate
and multimeter from the interphone test set.
interphone control VOL control fully clockwise;
